Southfield is a city in Oakland County in the U.S. state of Michigan. An inner-ring suburb of Detroit, Southfield borders Detroit to the north, ro…Southfield is a city in Oakland County in the U.S. state of Michigan. An inner-ring suburb of Detroit, Southfield borders Detroit to the north, roughly 15 miles northwest of downtown Detroit. As of the 2020 census, the city had a population of 76,618.