Route 175 is a short, 2.95-mile (4.75 km) long state highway in Mercer County, New Jersey, United States. The route runs along a former alignment of New Jersey Route 29 before the construction of the John Fitch Parkway in the 1960s. The route begins at Route 29 in the capital city of Trenton, running along Sanhican Road, River Road and West Upper Ferry Road into Ewing Township. The route serves primarily as a frontage road for Route 29. The northernmost portion of Route 175 is parallel to the Delaware and Raritan Canal until coming to an end at a merge with Route 29 in Ewing Township.