Passing through sparsely-populated areas of boreal forest, it serves as the sole land access route for the communities of Fort Liard and Nahanni Butte.

The highway begins at a point on the Alaska Highway 28 km (17 mi) northwest of Fort Nelson and runs 138 km (86 mi) northeast through expanses of the Canadian Boreal Forest to the border of British Columbia and the Northwest Territories.

Beyond the border, it continues for 254 km (158 mi) as a very rough packed dirt and gravel road designated as Highway 7.

[5] In 2012, Peter's Bros. Construction Ltd. was awarded a contract valued at $8,911,212.00 to pave (level course and overlay) over the existing sealcoat from the end of the existing pavement at 83 km (52 mi) in British Columbia to the border with the Northwest Territories, at 137 km (85 mi).

[citation needed] As of 2018, Highway 77 has been fully paved up to the border with the Northwest Territories.