Its western terminus is along US 6 at US 20 in Euclid, and its eastern terminus is at the Pennsylvania state line about 10 miles (16 km) south-southeast of Conneaut; Pennsylvania Route 226 continues eastward.

A portion of SR 84 runs along the historic Johnnycake Ridge Road.

Route 84 was established in 1923[7] and originally ran from 1-mile (1.6 km) south of Madison to 2 miles (3.2 km) west of Andover along the current alignment of State Route 307; from 1-mile (1.6 km) south of Madison to Dorset; and from Dorset to West Andover.

[8] It was expanded in 1926 to Willoughby Hills along a previously unnumbered road.

The former alignment from south of Madison to Dorset was certified as State Route 307.