The following highways are numbered 661:
| Preceded by 660 | Lists of highways 661 | Succeeded by 662 |
State Route 82 (SR 82) is a primary state highway in central Russell County, Virginia, United States. Known as Cleveland Road for most of its length, the route runs 6.84 miles (11.01 km) from SR 600 (SR 600) and SR 661 (SR 661) in Cleveland to U.S. Route 19 Business in Lebanon, providing a mountain crossing connecting the two towns.
State Route 661 (SR 661) is a 22.22-mile (35.76 km) long north–south state highway in the central portion of the U.S. state of Ohio. The southern terminus of SR 661 is at a diamond interchange with SR 16 and SR 37 just 0.25 miles (0.40 km) south of Granville. SR 661 has its northern terminus at a signalized T-intersection with SR 13 in the southern end of Mount Vernon.
State Route 6 (SR 6) is a state highway that is unsigned. It travels through the central part of the U.S. state of Tennessee from Lawrence County to Sumner County. The highway is related to the following U.S. Highways:
North Carolina Highway 66 (NC 66) is a 47.0-mile (75.6 km) North Carolina state highway that travels from Horneytown to Johnstown, connecting the towns and communities of eastern Forsyth and Stokes counties.
