Its northern terminus is at its junction with State Route 73 about 10.5 miles (16.9 km) north of Seaman, just inside of the Adams-Highland County Line.

State Route 770 is located entirely within the northern portion of Adams County.

The route is not incorporated as a part of the National Highway System.

[2] 1937 marked the year in which State Route 770 made its debut.

Heading west-to-east through the original southern terminus in 1937 was the former State Route 74, State Route 32's predecessor.