Allentown is a small historic borough in the far western corner of Monmouth County, New Jersey, directly bordering Mercer County to the west. With a population of about 1,700 and an area of roughly six-tenths of a square mile, it is one of the most compact municipalities in the region, known for the density of its preserved early architecture. The settlement dates to 1706, when Nathan Allen built a mill that anchored a growing colonial village. As surrounding farms prospered, Allentown filled in with the blacksmith shops, wheelwrights, and other trades that supported an agricultural economy, and by 1889 it was incorporated as a borough from portions of Upper Freehold Township. Its location along colonial roadways and waterways made it a crossroads for travelers between the Delaware River and the Jersey Shore. Allentown's defining feature is its historic fabric. The borough counts more than 200 homes on state and national historic registries, many dating before 1860, clustered around Main Street and the old mill. The Allentown Mill, built in 1855 to replace Nathan Allen's original 1706 structure, remains the town's landmark building, and the surrounding Allentown Historic District preserves one of New Jersey's most complete small-town colonial and Federal-era streetscapes. Today the borough is a quiet, walkable residential community. Its parks offer boat access, fishing, and recreational facilities, and the surrounding Upper Freehold countryside remains largely agricultural. Route 539 runs through town, and nearby Interstate 195 connects Allentown to the Trenton and Princeton area and to the New Jersey Turnpike, giving residents a rural, historic setting within commuting reach of central New Jersey employment centers.