The following highways are numbered 12F:
New York State Route 12E (NY 12E) is a state highway located entirely within the northwestern part of Jefferson County in northern New York in the United States. The southern terminus is at NY 12F in the village of Brownville. Its northern terminus, both signed and official, is at NY 12 in the village of Clayton. While NY 12 follows a direct north–south routing between Watertown and Clayton, NY 12E diverges westward to follow the shoreline of Lake Ontario. The portion of NY 12E north of its junction with NY 180 is part of the Seaway Trail, a National Scenic Byway.
New York State Route 12F (NY 12F) is an east–west state highway in Jefferson County, New York, in the United States. It extends for 6.89 miles (11.09 km) from an intersection with NY 180 in the town of Hounsfield to a junction with U.S. Route 11 (US 11) and NY 12 in the city of Watertown. The route follows a parallel routing to that of NY 12E between the vicinity of the village of Dexter and the city of Watertown. While NY 12E runs along the north side of the Black River through this area, NY 12F follows the southern bank. Just east of NY 180, NY 12F serves Watertown International Airport.
State Route 409 (SR 409) is a short Washington state highway in Wahkiakum County. The highway runs north from the Wahkiakum County Ferry on Puget Island to SR 4 in the county seat of Cathlamet over a distance of 3.84 miles (6.18 km). The route connects Westport, Oregon, which is served by the county ferry, and Cathlamet. The highway was referred to as Secondary State Highway 12F (SSH 12F) from 1943 until 1964.
