The Steepest Highway in North Carolina Is a Terrifyingly Treacherous Path

Written by Kathryn Koehler
Updated: August 30, 2023
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Picture if you will a trucker navigating the terrifyingly treacherous terrain of a steep mountain pass, a seemingly invincible road warrior. Yet, beneath the veneer of confidence, there’s an ever-present worry that can make even the toughest trucker apprehensive: the very real threat of brakes overheating or failing. Imagine the trucker’s heart racing, as they apply near-constant pressure to their brakes in an attempt to conquer the harrowing descent. It’s a reminder that, in the face of gravity, even the boldest truckers can feel a shiver down their spine. Any trucker or RV driver who has tackled North Carolina State Highway 226 in McDowell County is sure to know the feeling. The section of Highway 226 that runs through McDowell County is known for a three-mile stretch with 10 to 14% grades. This makes Highway 226 the steepest highway in North Carolina. Continue reading to discover more about this terrifyingly treacherous path.

Steep Hill Descent Use Low Gear Traffic Sign on the Road in Mountain

Even the boldest truckers can feel a shiver down their spine when tackling a steep descent.


The Steepest Highway in North Carolina: Highway 226

North Carolina State Highway 226 in McDowell County, from US 221 to the Blue Ridge Parkway, is a two-lane road. It has 11-foot lanes, minimal shoulders, and minimal existing right-of-way. The road is exceptionally curvy with a 3-mile section with grades of up to 14%. Thankfully, several safety features are in place. These include climbing lanes, signs warning truckers of the dangerous grades and curves, and advising them of the runaway ramps.

The Steepest Highway in North Carolina: Grading Method

The steepness of a highway, also known as its grade or gradient, is typically expressed as a percentage. This value indicates the change in elevation over a certain distance. It’s a measure of how steep or gradual a slope is. The calculation of the steepness of a highway involves determining the vertical rise (or fall) and dividing it by the horizontal distance covered.

The change in elevation between two points on the highway is measured using surveying tools, GPS devices, or elevation data from maps. The horizontal distance is measured along the surface of the road. The vertical rise or fall is then divided by the horizontal distance and multiplied by 100. Grade percentage = (Vertical Rise / Horizontal Distance) × 100. For example, if you have a highway segment where the vertical rise is 100 feet and the horizontal distance is 1000 feet, the grade percentage would be: (100 / 1000) × 100 = 10%

Grading System

Steepness grades on roads and highways are commonly classified using a system that categorizes them based on the percentage of incline (or decline). This classification helps drivers understand the challenges and limitations they might face when navigating these grades. Specific percentages may vary slightly among different systems, but generally follow along the lines of:

  • Slight Grade (1% to 3%): This is a gentle incline that most vehicles can easily handle. It might slightly affect speed and fuel efficiency, but it’s generally not a significant challenge.
  • Moderate Grade (4% to 6%): This grade is steeper than a slight grade and can require some downshifting. Trucks and vehicles carrying heavy loads might experience reduced speed and increased engine effort.
  • Steep Grade (7% to 10%): Steeper grades demand more attention and effort from drivers. Trucks and vehicles towing trailers may need to downshift, and some drivers might experience slower speeds and reduced fuel efficiency. Proper braking techniques are important on downhill portions.
  • Very Steep Grade (11% to 15%): This grade is quite challenging, especially for heavy vehicles. Downshifting and careful control of speed are necessary to prevent brake overheating on descents. Many vehicles will struggle to maintain high speeds on ascents.
  • Extremely Steep Grade (Over 15%): Extremely steep grades are very difficult to navigate, especially for large vehicles. These grades require advanced driving techniques and extra precaution. . Trucks might need to use lower gears and maintain slower speeds for safety.
Stock Photo ID: 1212581008 Smoky Mountains near Asheville, North Carolina at Tennessee border during sunny spring day, sky, green trees, highway road

Steepness classifications help drivers, especially truck drivers and those operating large vehicles, understand the challenges and limitations they might face when navigating a steep highway.

©Kristi Blokhin/

The Steepest Highway in North Carolina: Relatively Speaking

Though U.S. Interstate Highways have regulations in place limiting them to a maximum grade of 6%, U.S. State highways have no such regulations. With 15% grades, North Carolina State Highway 226 is classified as extremely steep. So, how does it compare to other steep highways around the world? Let’s see!

HighwaySteepest Grade
 Waipio Valley Road, Big Island, Hawaii45%
Baldwin Sreet, Dunedin, New Zealand35%
Sonora Pass, Alpine, Mono, Tuolumne Counties, California26%
Mount Washington Auto Road, Gorham, New Hampshire:20%
North Carolina State Highway 226, McDowell, County, North Carolina:15%
Brenner Pass, Innsbruck, Austria:9.7%
Slumgullion Pass, Colorado State Highway 149, Lake City, Colorado:9%
Mounteagle Mountain, U.S. Interstate Highway 24, Tennessee:5%

Blue Ridge Mountains

North Carolina State Highway 226 in McDowell County is located in the Blue Ridge Mountains. Stretching from Georgia to Pennsylvania, they are a part of the larger Appalachian Mountains system. One of the more famous attractions within the Blue Ridge Mountains is the Blue Ridge Parkway. It is a scenic highway that winds through the mountains and offers breathtaking vistas. The Appalachian Trail, a long-distance hiking trail stretching from Georgia to Maine, passes through the Blue Ridge Mountains, drawing hikers from around the world.

Blue Ridge Parkway vista - a bridge over the French Broad River in springtime, Asheville, North Carolina

One of the more famous attractions within the Blue Ridge Mountains is the Blue Ridge Parkway.

©Alex Krassel/

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

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About the Author

Kathryn Koehler is a writer at A-Z-Animals where her focus is on unusual animals, places, and events. Kat has over 20 years of experience as a professional writer and educator. She holds a master's degree from Vanderbilt University. When she is not writing for A-Z-Animals, Kat enjoys puttering in her garden, baking deliciously healthful treats for her family, and playing with her two rescue mutts, Popcorn and Scooter. She resides in Tennessee.

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