Milton is a borough in Northumberland County, Pennsylvania, United States, on the West Branch Susquehanna River, 50 miles (80 km) north of Harrisburg, located in Central Pennsylvania’s Susquehanna River Valley. It is approximately 10 miles upriver from the mouth of the West Branch Susquehanna River and practically 30 miles downriver of Williamsport.

Settled in 1770, Milton was incorporated in 1817, and is governed by a charter that was revised in 1890. Formerly, its extensive manufacturing plants included car and woodworking machinery shops; rolling, flour, knitting, planing, and motto mills; washer, nut, and bolt works; and furniture, shoe, couch, nail, fly net, bamboo novelty, and paper-box factories. In 1900, 6,175 people lived in Milton. In 1940, 8,313 people lived there. The population was 6,650 at the 2000 census, and 7,042 at the 2010 census.

The Milton Historic District, Pennsylvania Canal and Limestone Run Aqueduct, Milton Armory, and Milton Freight Station are listed on the National Register of Historic Places.

At the face of the 20th century, several industrial and manufacturing companies were located within the borough. The six principal industries were Samuel J. Shimer & Sons, the Milton Manufacturing Company, the American Car and Foundry Company, the F.A. Godcharles Company, the Sydney H. Souter Silk Company, and the West Branch Novelty Company. Many smaller businesses flourished in parallel in imitation of the large manufacturing companies during this in advance period, which made the borough an industrial middle in the region at the time.