Discover the Oldest Lake in Canada

Written by Ashley Day
Updated: August 9, 2023
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What Was the Oldest Lake in Canada and Where Was It Located?

Lake Agassiz, a prehistoric glacial lake, was one of the oldest lakes in Canada. It once sprawled across what we know today as southeastern Manitoba, northwestern Ontario, northern Minnesota, eastern North Dakota, and Saskatchewan. It was a mammoth body of water formed during the late Pleistocene Epoch (approximately 2.6 million to 11,700 years ago), the last ice age. At its peak, this lake spanned a surface area of about 100,387 square miles (260,000 square kilometers). Its maximum length was roughly 475 miles (764 kilometers), while its maximum width was 296 miles (476 kilometers).

Argentina, Glaciers national park, Icebergs of Spegazzini glacier

Lake Agassiz was the oldest lake in Canada.


History of Lake Agassiz and Lakes of the Agassiz Basin

Lake Agassiz was named after the Swiss-American geologist Louis Agassiz. He was both a geologist and naturalist, and he specifically focused his studies and research on the movement of glaciers. This ancient lake was a marvel of nature, leaving its mark on the landscape and shaping the environment in significant ways.

As the great glaciers receded during the waning years of the ice age, they left behind deep depressions in the terrain, forming basins that eventually filled with water. These melting ice sheets acted as a source, continually replenishing this lake’s waters, which carved out river valleys, shaped the land, and influenced the climate, sea level, and human civilization.

Lake Agassiz was not a stagnant body of water. Instead, it periodically drained and refilled due to ice dam breaches, leading to dramatic fluctuations in its size over time. The last significant drainage occurred around 8,200 years ago, marking the final stages of its existence. However, with its last drainage as a result of the remaining Hudson Bay ice melting, multiple lakes took form and still stand today.

As for the geological makeup of the lake, it is comprised of sediment, rocks, and minerals that accumulated over millennia. As the glaciers melted, they deposited immense amounts of sediment, creating the lake bed and shaping the surrounding landscapes. Over time, the water’s action and the flow of rivers further shaped the lake’s shores and contributed to the diverse geology of the region. Additionally, the fine claylike silt that accumulated on the bottom of Lake Agassiz resulted in the rich fertility of the area’s valleys and rivers.

Great Lakes of Manitoba and Lake of the Woods

Today, the remnants of Lake Agassiz can still be seen in various forms of other lakes. Concerning the Canadian region, the Agassiz Basin provided the perfect conditions for the formation of some of the other oldest lakes in Canada. They include the Great Lakes of Manitoba (Lake Winnipeg, Lake Manitoba, and Lake Winnipegosis) and Lake of the Woods, spanning the Canadian provinces of Ontario, Manitoba, and the U.S. State of Minnesota. 

The Great Lakes of Manitoba geology mirrors that of their parent lake, Lake Agassiz. These freshwater bodies now rest upon layers of sediment and glacial deposits, showcasing the legacy of the last ice age. River systems, fed by melting ice and precipitation, have continued to shape the landscapes around the Great Lakes, adding to their geological diversity.

Lake Winnipeg, the largest of the Great Lakes of Manitoba, is now the tenth-largest freshwater lake globally and covers a vast expanse. Lake Manitoba, Lake Winnipegosis, and Lake of the Woods though smaller, still rank among the most significant freshwater bodies in the region. Scientists continue to study the legacy of this ancient lake, unearthing vital clues about the Earth’s past and how its natural processes have shaped the world we know today.

Lake Winnipeg near Camp Morton, Gimli MB

With the last drainage of Lake Agassiz roughly 8,000 years ago, the Great Lakes of Manitoba formed.


Can You Swim in the Great Lakes of Manitoba?

Swimming in the Great Lakes of Manitoba, some of the oldest lakes in Canada offers a refreshing and enjoyable experience for locals and visitors alike. Lake Winnipeg, the largest of the Great Lakes in the region, boasts beautiful beaches and clear waters that beckon swimmers during the summer months. Although smaller, Lake Manitoba and Lake Winnipegosis also provide ample opportunities for swimming and water-based activities.

During the summer, the water temperature of the Great Lakes of Manitoba tends to be pleasantly mild, fair for swimming and other recreational pursuits. On average, Lake Winnipeg’s water temperature ranges from around 55 to 70 degrees Fahrenheit (12.8 to 21.1 degrees Celsius) during the summer season. Lake Manitoba and Lake Winnipegosis generally have similar temperature ranges during this time.

Water Temperature of The Great Lakes of Manitoba

In contrast, the water temperature of these lakes in winter drops significantly due to freezing temperatures and ice cover. During the colder months, the lakes can freeze over, creating a stunning icy landscape perfect for ice skating, ice fishing, and other winter activities.

The Great Lakes of Manitoba boast several sandy beaches that attract sun-seekers and those looking to hit the beach. Grand Beach Provincial Park, located on the southeastern shore of Lake Winnipeg, is one of the most popular destinations. With its vast expanse of soft, sandy shoreline, it offers an idyllic setting for relaxing, sunbathing, picnics, beach volleyball, and, of course, swimming. As with any aquatic environment, swimmers should exercise caution and be aware of water conditions, such as currents and water depth, to ensure a safe and enjoyable swimming experience.

Apart from the beaches, the lakes’ surrounding areas also offer camping, hiking, and wildlife observation opportunities. The lakes are teeming with diverse aquatic life, and birdwatchers will be delighted by the abundance of bird species that inhabit the region.

Overall, the Great Lakes of Manitoba provide a haven for swimmers, nature enthusiasts, and those seeking outdoor adventures. With their inviting beaches and pleasant water temperatures during the summer, these lakes offer a delightful escape into the beauty of Manitoba’s natural landscape.

Two athletes swimming in a lake panorama

Swimming in any of the Great Lakes of Manitoba is a great way to stay cool in the summer months.


Recreational Activities at the Great Lakes of Manitoba

The Great Lakes of Manitoba, a natural wonder that adorns the Canadian landscape, offers a vast array of exhilarating activities for outdoor enthusiasts seeking to forge unforgettable memories. From water-based adventures like fishing, boating, and kayaking to winter wonders such as ice fishing and snowshoeing, the region boasts something for everyone.


As some of the oldest lakes in Canada, The Great Lakes of Manitoba provide an angler’s paradise with diverse fish species. Cast your line into the sparkling waters and try your luck catching prized fish. Ice fishing becomes a cherished pastime when winter embraces the landscape with its icy grip. Drill holes in the frozen lakes and reel in fish like trout and whitefish, relishing the thrill of fishing in an enchanting winter wonderland.


Non-motorized and motorized boating is an excellent opportunity to experience the vast Great Lakes of Manitoba. Boat across the tranquil surfaces of the lakes, breathing in the crisp, fresh air and soaking in the scenic beauty surrounding you. Boating offers a serene escape and the perfect opportunity to marvel at the wonders of nature.

Winter Exploration

Traverse through the pristine winter landscapes surrounding the Great Lakes of Manitoba or on the frozen surfaces by snowshoes, cross-country skis, or even snowmobiles. Discover the untouched beauty of snow-laden forests and frozen shores while immersing yourself in the tranquility of the season.


Delve into the depths of the Great Lakes of Manitoba to uncover the underwater world. Scuba diving and snorkeling here reveal captivating mysteries, fascinating underwater artifacts, and a diverse aquatic ecosystem that will leave you mesmerized.

Paddle Boarding, Canoeing, and Kayaking

Glide serenely across the clear waters of the Great Lakes of Manitoba, exploring hidden coves, traveling along the shorelines, and marveling at the diverse birdlife that calls these shores home. Paddle boarding, canoeing, and kayaking offer a unique perspective of the region’s natural wonders.

Waterskiing, Wakeboarding, and Tubing

For thrill-seekers, waterskiing and wakeboarding on the surfaces of the Great Lakes of Manitoba provide an adrenaline-pumping experience. Hold tight as you’re towed behind a boat, feeling the rush of excitement as you glide over the water.


If sailing is of interest, look no further. The Great Lakes of Manitoba offer a fantastic opportunity to get on the water. Raise your sails and let the gentle winds carry you across the vast expanses of the Great Lakes. Sailing enthusiasts will find a serene and liberating experience amidst the picturesque beauty of the region.

Hiking, Camping, and Backpacking

Explore the diverse landscapes surrounding the Great Lakes of Manitoba through an extensive network of hiking trails. From leisurely nature walks to complex backpacking adventures, visitors can bask in the grandeur of scenic vistas, diverse flora, and occasional wildlife encounters.

Birdwatching and Wildlife Viewing

The Great Lakes of Manitoba attract a wide variety of bird species, making it a birdwatcher’s paradise. Keep an eye out for waterfowl, raptors, and songbirds as you witness the splendor of nature’s vibrant winged inhabitants. Additionally, the diverse wildlife provides plentiful opportunities to experience the abundance of the natural world.


Grab your climbing shoes and bouldering pads! For those who like to climb rocks without ropes, there are various boulders scattered across this region, offering opportunities to enjoy the local rocks and geology.

Guided Tours

Embark on informative guided tours that delve into the lakes’ ecological wonders, indigenous heritage, and conservation efforts. Expert guides will lead you through a deeper understanding of this unique ecosystem.

Scenic Flying

Experience the awe-inspiring aerial view of some of the oldest lakes in Canada and their surroundings with a scenic flight. Witness the grandeur of the lakes from above, capturing the true essence of this natural marvel.

Tip of the canoe pointing out into the water toward the sunset, Hecla Island, Lake Winnipeg, Manitoba

Canoeing and kayaking are popular activities on Lake Winnipeg, Lake Manitoba, and Lake Winnipegosis.


Camping and Provincial Parks at the Great Lakes of Manitoba


Embark on an enchanting camping adventure along the shores of some of the oldest lakes in Canada, which include Lake Winnipeg, Lake Manitoba, and Lake Winnipegosis. These serene lakes offer a variety of campgrounds where you can immerse yourself in the natural beauty of the region. Prepare to pitch your tent, stargaze under clear skies, and create cherished memories with family and friends.

Grand Beach Provincial Park (Lake Winnipeg)

Located on the eastern shore of Lake Winnipeg is Grand Beach Provincial Park. It is a beloved destination for campers seeking a blend of stunning landscapes and beachfront bliss. The park’s campground offers modern amenities and well-maintained facilities, ensuring a comfortable camping experience. Wake up to the sound of gentle waves. Spend your days exploring the sandy beaches and hiking through scenic trails. Or simply bask in the sun-kissed beauty of the lake.

Camping on Hecla-Grindstone Provincial Park (Lake Winnipeg)

Situated on the southern end of Lake Winnipeg, Hecla-Grindstone Provincial Park invites campers to embrace the wonders of nature. The park features multiple campgrounds, including Hecla Village Campground, Grassy Narrows Campground, and Gull Harbour Campground. Each campground offers a unique experience, from lakeside views to forested settings. Enjoy wildlife viewing, birdwatching, and many recreational activities, making it an ideal destination for nature enthusiasts.

Manipogo Provincial Park (Lake Manitoba)

Nestled near the shores of Lake Manitoba, Manipogo Provincial Park presents a secluded camping oasis that isn’t well-known. This wilderness park provides a camping experience for those seeking solitude and a connection with nature. While amenities are minimal, campers can relish the peaceful ambiance, hike through serene trails, and spot wildlife in its natural habitat.

Steep Rock Beach Park (Lake Manitoba)

Tucked along the northeastern shore of Lake Manitoba is Steep Rock Beach Park. It entices campers with its rugged cliffs and scenic vistas. The campground and cabins provide a serene retreat where you can unwind by the water’s edge and admire breathtaking sunsets. Explore the nearby cliffs, relax on the sandy shores, and indulge in the tranquility of nature.

Winnipegosis Beach & Camp Ground (Lake Winnipegosis)

Located on the southern end of Lake Winnipegosis, this comfortable campground offers plentiful amenities in a nature setting. Pitch your tent or pull up your RV, listen to the sounds of nature, and savor the peace and seclusion of this camping experience.

Please note that availability and amenities at these campgrounds may vary. It’s essential to check with park authorities or the official websites of campgrounds for up-to-date information and reservations. Whether seeking sandy beaches, serene sunsets, or wilderness solitude, the Great Lakes of Manitoba campgrounds promise a genuinely unforgettable camping experience.

Provincial Parks

The Great Lakes of Manitoba are surrounded by provincial parks that offer even more recreational opportunities. Nature enthusiasts and adventurers alike can immerse themselves in outdoor and wilderness settings. Each provincial park is teeming with beauty and tranquility. They offer a range of activities that allow visitors to connect with nature and experience this region’s unique charm.

Most prominently, the parks offer hiking trails that wind through lush forests, open meadows, and along the lakeside, allowing visitors to explore the diverse landscapes and observe the native flora and fauna. It is a rewarding way to connect with nature and discover hidden gems along the trails.

As you traverse the park’s trails, keep your eyes peeled for the abundant wildlife that calls this area home. From deer and moose to various bird species, you may be treated to memorable wildlife encounters that showcase the park’s natural biodiversity. It is also a birdwatcher’s paradise, providing ample opportunities to spot various bird species. Bring your binoculars and marvel at the sight of waterfowl, songbirds, and raptors soaring through the skies.

Those who enjoy photography will find endless inspiration at any of the parks. Capture the beauty of the landscapes and the play of light on the water. As well as the fascinating wildlife that inhabits the area.

Water Activities

As for water activities, the parks present the chance to indulge in various types of fishing. Cast your line into the lake’s waters, and you may be rewarded with catches like northern pike, walleye, and perch. The serene surroundings and access to the lake make it an ideal destination for those wanting to get out on the boat. This includes both motorized and non-motorized vessels, such as canoeing and kayaking. Glide along the tranquil waters, exploring shorelines and embracing the peace of the lake.

Other Activities

Other activities visitors can enjoy around some of the oldest lakes in Canada include the following. You can also plan a delightful picnic by the lakeshore or in a scenic clearing within the parks. Enjoy a leisurely meal amidst nature’s splendor, with the sounds of the breeze and the lapping of the water enhancing your outdoor dining experience. As the sun sets, the parks offer a splendid opportunity for stargazing. Far from city lights, the park’s dark skies provide a canvas for an awe-inspiring display of stars, planets, and celestial wonders.

Once winter hits, there are plentiful opportunities to explore the landscape and frozen lake. They include cross-country skiing, snowshoeing, snowmobiling, and other means. Ice fishing is another popular winter activity. Furthermore, one of the most rewarding activities at these parks is simply appreciating the pristine beauty of nature. Take a moment to be present in the surroundings, relishing the tranquility and serenity that only nature can provide.

It is also worth noting that the parks may have limited amenities or regulations. Visitors should come prepared with supplies and practice Leave No Trace principles to preserve the various parks’ natural integrity.

Grand Beach Provincial Park

Located on the southeast shore of Lake Winnipeg is Grand Beach Provincial Park. It boasts a stunning sandy beach, hiking trails, picnic areas, and camping facilities.

Hecla-Grindstone Provincial Park

Situated on the southern end of Lake Winnipeg, this park offers a diverse landscape with forests, wetlands, and rugged shorelines. Visitors can enjoy hiking, biking, golfing, birdwatching, and fishing.

Manipogo Provincial Park

The Great Lakes of Manitoba are a haven for adventure seekers. They offer a captivating blend of natural wonders and thrilling activities for every interest. Whether you seek the tranquility of fishing, the excitement of water sports, or the serenity of winter exploration, these lakes beckon you to immerse yourself in the beauty of the great outdoors.

Hecla-Grindstone Provincial Park includes Hecla Island, Grindstone, the area located on the mainland peninsula along the west shore of Lake Winnipeg which is the largest freshwater lakes in the world.

Hecla-Grindstone Provincial Park offers plentiful recreation activities to enjoy Lake Winnipeg.

©Angelito de Jesus/

Animal and Plant Species Found in the Great Lakes of Manitoba

The Great Lakes of Manitoba are some of the oldest lakes in Canada. They include Lake Winnipeg, Lake Manitoba, and Lake Winnipegosis. All of which host a wide variety of aquatic and terrestrial life within a thriving ecosystem.

Fish Species

The pristine waters of these lakes host an impressive array of fish species. Anglers can cast their lines in search of prized catches such as walleye, northern pike, yellow perch, and lake whitefish. These lakes are also home to other fish species like sauger, goldeye, and mooneye, creating a haven for fishing enthusiasts.

Wildlife Species

Diverse land animals roam on the shores and surrounding areas, seeking shelter and sustenance. You may encounter majestic mammals like white-tailed deer, moose, and black bears. At the same time, smaller creatures like red foxes and coyotes stealthily traverse the landscape. The region’s forests and grasslands echo the sounds of many species of songbirds. Raptors also soar through the skies in search of prey.

Aquatic Species

Beneath the lake’s shimmering surface, a bustling underwater world thrives. From tiny aquatic insects to crayfish and freshwater mussels, a diverse community of organisms forms the foundation of the lake’s food chain. Additionally, beavers, muskrats, and otters leave their mark along the water’s edge, building dams and lodges.

Bird Species

The Great Lakes of Manitoba serve as crucial habitats for an impressive assortment of bird species. Graceful waterfowl like Canada geese, mallards, and common loons make these lakes their home. In contrast, migratory birds like tundra swans and snow geese pass through during their seasonal journeys.

Plant Species

The flora surrounding the Great Lakes of Manitoba contributes to the region’s natural beauty and ecological balance. Lush forests consist of black spruce, white spruce, trembling aspen, and balsam poplar, providing vital habitat for wildlife. Along the lakeshores, aquatic plants like bulrushes, cattails, and water lilies flourish, offering shelter and breeding grounds for various aquatic species.

Rain Date - A bull moose wades through the water in search of a cow moose during the fall mating season in the rain. Baxter State Park, Millinocket, Maine.

The Great Lakes of Manitoba are home to many species, including moose.

©Richard Seeley/


Lake Agassiz is one of the oldest lakes in Canada. It was an ancient glacial lake that once dominated the region and shaped the landscape of this region of Canada. As it receded, it left behind the Agassiz Basin, which birthed the Great Lakes of Manitoba. These lakes, still standing today in Canada, consist of Lake Winnipeg, Lake Manitoba, and Lake Winnipegosis. These lakes now thrive with diverse fish species, abundant wildlife, and lush plant life. Each lake offers a plethora of recreational activities, from fishing and boating to hiking and birdwatching. The Great Lakes of Manitoba continue to enchant nature enthusiasts and scientists. Their natural beauty and ecological significance make them a cherished destination for those seeking to connect with the wonders of the natural world.

The photo featured at the top of this post is © wlkellar/

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About the Author

Ashley is a writer for A-Z Animals, where her primary focus is on wildlife, nature conservation, the environment, and pets. As a writer and wildlife photographer, Ashley has been writing, photographing, and researching about animals and the environment for over eight years. Ashley is a resident of the Pacific Northwest, where she enjoys being out in nature, hiking, and scouring local bookshops. Insatiably curious and drawn to knowledge, she has a passion for sharing the wonder of the natural world with others.

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