King's Highway 37, commonly referred to as Highway 37, is a provincially maintained highway in the Canadian province of Ontario. It begins at Highway 401 in Belleville and travels 44.2 km (27.5 mi) north to Highway 7 in Actinolite. The route once continued south through Belleville to Highway 62, but was truncated in 1998. Prior to the re-routing, Highway 37 was 47.2 km (29.3 mi) long.