The Middletown Mansfields were a baseball team in Middletown, Connecticut. The Mansfields were a member of the National Association in 1872. The team was organized by Ben Douglas Jr., who named the team after his great-uncle General Joseph Mansfield. They were managed by catcher John Clapp, and they finished with a record of 5-19. Their home games were played at the Mansfield Club Grounds in Middletown, Connecticut. Though based in Middletown, they were normally listed as simply "Mansfield" or "the Mansfields" in game reports. "Middletown Mansfields" is modern nomenclature.
Among their players was future Hall of Fame outfielder Jim O'Rourke, who was a 21-year-old rookie. He batted .307 in 23 games at shortstop, catcher, and third base. Also on the team was the star pitcher for the undefeated 1869 Cincinnati Red Stockings, Asa Brainard. Another player on the team was Ham Allen who batted .271 in 17 games.
Obstacles for a small town like Middletown to operate and compete against big city teams like Boston, New York, and Baltimore were many, so on August 14, 1872, closed their books and ended their one and only major league season.