Sullivan (formerly Winfield) is a village in Jefferson County, Wisconsin, United States.

The village is located within the Town of Sullivan, and is known to residents of southern Wisconsin including the Madison and Milwaukee metro areas as the location of the National Weather Service forecast office MKX, although its mailing address is in nearby Dousman.

According to the United States Census Bureau, the village has a total area of 1.14 square miles (2.95 km2), all land.

There were 328 housing units at an average density of 287.7 per square mile (111.1/km2).

36.2% of all households were made up of individuals, and 12.8% had someone living alone who was 65 years of age or older.

There were 321 housing units at an average density of 286.6 per square mile (110.7/km2).

30.5% of all households were made up of individuals, and 9.7% had someone living alone who was 65 years of age or older.