Middlefield is a town in Middlesex County, Connecticut, United States. The population was 4,203 at the 2000 census. The town includes the village of Rockfall Middlefield, in Middlesex County, is so named because it is halfway between Middletown and Durham, and Middletown and Meriden. For such a small community, Middlefield has an abundance of wonderful history that goes back to the late 17th century and many first settlers of Connecticut. The Old North Burying Ground was established for those living west of Middletown and the first burial was in 1738.