The section of PA 194 south of Hanover was part of the 18th-century Monocacy Road which connected Hanover to Frederick, Maryland. In the 19th century, the road between Littlestown and Hanover was the Hanover and Littlestown Turnpike while the road between Hanover and East Berlin was the Hanover and East Berlin Turnpike, both private turnpikes. In 1928, PA 194 was designated between US 140 (now PA 97) in Littlestown and PA 74 in Dillsburg along a paved road. Two years later, the route was extended from Littlestown to the Maryland border. The road was widened in the Hanover area in the 1940s and split into a one-way pair in downtown Hanover along with PA 116 by 1965. In 2002, a roundabout was constructed at the intersection with US 30 in Abbottstown.