The East River Mountain Tunnel is a 5,412-foot (1,650 m) vehicular tunnel that carries Interstate 77 (I-77) and U.S. Route 52 (US 52) through East River Mountain between Bluefield, West Virginia, and Rocky Gap, Virginia.

At a cost of $40 million (equivalent to $192 million in 2023[1]), it was the most expensive construction project undertaken by the West Virginia Division of Highways at the time.

[2] Before the opening of the East River Mountain Tunnel, travelers wishing to cross the state line had to navigate the narrow, twisting, guardrail-less route of US 52 up and over the mountain (now designated as SR 598 and WV 598).

When fog or snow was present, the journey became arduous, and the road was occasionally closed completely (particularly in the winter months) due to treacherous conditions.

[2] The top of East River Mountain can be seen in the distance from Big Walker Lookout, a 100-foot (30 m) observation tower built on Big Walker Mountain.