State Route 366 is an east–west state highway in the western portion of the U.S. state of Ohio. SR 366 has its western terminus at a T-intersection with U.S. Route 33 nearly 1.50 miles (2.41 km) northwest of Lakeview. The route's eastern terminus is at State Route 117 about 1.50 miles (2.41 km) north of Huntsville. SR 366 runs along the western and southern edge of Indian Lake and provides access to homes and recreational facilities along the lake shoreline. SR 366 was designated in 1939, and was extended in 1961.

U.S. Route 33 (US 33) is a United States Numbered Highway running from near Elkhart, Indiana, to Richmond, Virginia. Within the state of Ohio, it is a predominantly southeast–northwest highway running from west of Willshire before crossing over into West Virginia via the Ravenswood Bridge over the Ohio River. The route runs through largely rural territory throughout most of the state's west-central, central, and southeastern regions, although it also passes through large portions of downtown Columbus.