Princeton, MO

Princeton is Mercer County's seat and largest city, centered in northern Missouri on U.S. 65. The 2020 census counted 1,007 residents. The highway runs along the east side of town, 24 miles north to Trenton and 13 miles south to Lineville, Iowa. The Weldon River drains the area toward the Thompson and Grand rivers, giving the county seat a landscape of fields, creeks, and long north-south roads. County offices and services give the town a role beyond its population. That civic role is visible in daily life.

The town was platted in 1846 and named for the Revolutionary War Battle of Princeton. It is also the birthplace of frontierswoman Calamity Jane, a detail that gives the courthouse town an outsized place in western folklore. Princeton R-V operates elementary, junior-high, and high-school programs, and the Mercer County Library adds another civic stop. The county seat's role is practical: schools, library, courthouse work, and U.S. 65 all keep Princeton connected to smaller communities across Mercer County.