Winfield is a town in Winfield Township, Lake County, Indiana. The population was 2,298 at the time of the 2000 census, 4,383 in 2010, and 5,987 in 2019. The town was incorporated in 1993 in order to keep the residents from being annexed by other neighboring communities. Prior to that time it had been part of Winfield Township as an unincorporated …Winfield is a town in Winfield Township, Lake County, Indiana. The population was 2,298 at the time of the 2000 census, 4,383 in 2010, and 5,987 in 2019. The town was incorporated in 1993 in order to keep the residents from being annexed by other neighboring communities. Prior to that time it had been part of Winfield Township as an unincorporated town. Winfield is named for General Winfield Scott. The town is served by the Crown Point post office and addresses in Winfield share the Crown Point ZIP code.