The land Mexico resides on was once part of Holmanstown Plantation, which was granted by the Massachusetts General Court in 1789 to Colonel Jonathan Holman of Sutton, Massachusetts (now Millbury) and others.
The plantation’s remaining portion, which had been first settled by Isaac Gleason, was incorporated on February 13, 1818 as the town of Mexico. The unique name to this area was inspired by local sympathy for the country of Mexico’s 1810–1821 fight for independence from Spain.
Then known as Mexico Corner, it developed as a farming community with mills at the streams. In 1894, George W. Ridlon, president of the Rumford Falls Brick Company, founded a settlement in the eastern part of the town called Ridlonville.