[4] Southgate was incorporated as a city on October 8, 1958, which was one of the last remaining portions of the now-defunct Ecorse Township.

Among the oldest residential areas in the city is the Old Homestead neighborhood, on the east side.

There are two accounts of the city's name: Southgate is described in local guides as the "South Gate" or entrance to the Metro Detroit area.

"We were trying to get a separate post office for our community, and were advised that it would help our cause if the township board passed a resolution creating an unincorporated village," Anderson explained.

Anderson had previously suggested the city be named Southgate due to its location south of Detroit.

Anderson became aware of South Gate, California near Los Angeles during World War II while temporarily stationed in San Diego.

"[10] Thomas Anderson became the first mayor in 1958 after being Ecorse Township's supervisor for the previous five years.

[citation needed] According to the United States Census Bureau, the city has a total area of 6.875 sq mi (17.81 km2), all land.

Southgate Community School District operates the following public schools:[16] Southgate currently houses the headquarters of The News-Herald, a local Downriver newspaper which covers over twenty surrounding communities.

During the late 1950s and 1960s, The Southgate Sentinel, a Mellus newspaper and forerunner to the present-day News-Herald, was published.

The Conrail Shared Assets Lincoln Secondary, used primarily by CSX Transportation freight trains that run between Detroit and Toledo, Ohio, runs through the northwest corner of Southgate and is notable for the large grade crossing (one of the largest in the world) through the intersection of Northline and Allen Roads, and also has a crossing at Reeck Road.

[citation needed] Four Suburban Mobility Authority for Regional Transportation bus routes pass through Southgate.