State Route 4, formerly known as Inter-county Highway 4 until 1921 and State Highway 4 in 1922, is a major north–south state highway in Ohio. It is the fifth longest state route in Ohio. Its southern terminus is at U.S. Route 42 in Cincinnati, Ohio, and its northern terminus is at U.S. Route 6 in Sandusky, Ohio. Its path is nearly ruler-straight for many miles. Some portions of the route are still marked as Dixie Highway. The northern portion was constructed by the Columbus and Sandusky Turnpike Company, see Turnpike Lands.

Middletown is a city located in Butler and Warren counties in the southwestern part of the U.S. state of Ohio. The population as of the 2020 census was 50,987. It is part of the Cincinnati metropolitan area, located 29 miles (47 km) northeast of Cincinnati and 20 miles (32 km) southwest of Dayton.