Ohio State Route 643

State Route 643
Route information
Maintained by ODOT
Length	16.35 mi[1][2] (26.31 km)
Existed	1937[3][4]–present
Major junctions
South end	SR 83 near Coshocton
North end	SR 93 near Baltic
Location
Country	United States
State	Ohio
Counties	Coshocton, Holmes
Highway system
Ohio State Highway System Interstate US State Scenic
← SR 640 → SR 644

State Route 643 (SR 643, OH 643) is a two-lane north–south state highway in the central portion of Ohio, a U.S. state. The highway's southern terminus is at a T-intersection with State Route 83 north of Coshocton. Its northern terminus is at a T-intersection with the concurrency of State Route 93 north of Baltic. A section of the route is part of a scenic byway.

The route was commissioned in the late 1930s. The northern terminus was relocated to a temporary end with Temporary SR 557, in late 1940s. The highway was paved during the 1950s and 1960s. In the late 1960s the highway's northern terminus was moved to its current location.