Princeton is a city in Mercer County, Missouri. The population was 1,166 at the 2010 census, an 11.4% increase in population from the 2000 census, which counted 1,047 people. It is the county seat of Mercer County.
Princeton is located at 40°23′56″N 93°35′9″W / 40.39889°N 93.58583°W / 40.39889; -93.58583 (40.398794, -93.585807). According to the United States Census Bureau, the city has a total area of 1.6 square miles (4.1 km²), of which, 1.6 square miles (4.1 km²) of it is land and 100.00% is water.
Princeton is the birthplace and childhood home of Calamity Jane. In recognition of this Princeton hosts Calamity Jane Days Fall Festival each September. Martha Jane Cannary (aka Calamity Jane) was born May 1, 1852 in Princeton, Missouri, the oldest of six children. She had two brothers and three sisters. Parents Robert W. and Charlotte Cannary are listed in the 1860 census living nearby in Ravanna, Mercer County, Missouri. The Cannary family moved to Montana in 1865, then on to Salt Lake City, UT where Robert Cannary died.