Pierre Michel Campau was the first white settler in Southgate. He moved into the area in 1795, which subsequently became a farming community. Other people from the Detroit area at the Rouge and Detroit Rivers followed him to Southgate.

Historically a rural area of Ecorse Township, the areas within present-day Southgate were originally platted with street grids beginning in the 1920s – though most developments only started just after World War II. 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. “A metropolitan daily picture story” in late 1956 also explained this.

Southgate’s first mayor, Thomas J. Anderson, also stated in 1956 that the name originated from the newly built Southgate Shopping Center at the southeast corner of Eureka & Trenton roads. “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. “The name Southgate was chosen because of the shopping center then under consideration, and the board agreed that it was an appropriate name. 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. The resolution was adopted at a regular meeting in the early summer of 1953.”

Thomas Anderson became the first mayor in 1958 after being Ecorse Township’s supervisor for the previous five years. Southgate Anderson High School was named after him in 1982. The flag for Southgate Michigan which was created in 1973.

According to the United States Census Bureau, the city has a total area of 6.875 sq mi (17.81 km), all land.

Southgate borders the cities of Riverview (south), Wyandotte (east), Allen Park (northwest), Taylor (west), and Lincoln Park (north), as well as Brownstown Charter Township (southwest).

As of the 2020 census, there were 30,014 people, 13,497 households, and 7,784 families residing in the city. The population density was 4,365.7/sq mi (1,685.6/km). There were 14,053 housing units. The racial makeup of the city was 77.9% White, 7.8% African American, 0.7% Native American, 2.5% Asian, 0.0% Pacific Islander, 2.5% from some other races and 8.6% from two or more races. Hispanic or Latino of any race were 9.1% of the population. 19.8% of residents were under the age of 18, 5.4% were under 5 years of age, and 18.7% were 65 and older.

As of the 2010 census, there were 30,047 people, 13,062 households, and 7,833 families residing in the city. The population density was 4,389.0/sq mi (1,694.6/km). There were 13,933 housing units at an average density of 2,034.0/sq mi (785.3/km). The racial makeup of the city was 88.7% White, 5.5% African American, 0.5% Native American, 1.6% Asian, 1.7% from other races, and 2.0% from two or more races. Hispanic or Latino of any race were 6.5% of the population.

There were 13,062 households, of which 27.4% had children under the age of 18 living with them, 42.6% were married couples living together, 12.3% had a female householder with no husband present, 5.0% had a male householder with no wife present, and 40.0% were non-families. 33.9% of all households were made up of individuals, and 14.1% had someone living alone who was 65 years of age or older. The average household size was 2.29 and the average family size was 2.95.

The median age in the city was 40.8 years. 20.3% of residents were under the age of 18; 9.1% were between the ages of 18 and 24; 26.2% were from 25 to 44; 28.2% were from 45 to 64; and 16.3% were 65 years of age or older. The gender makeup of the city was 47.9% male and 52.3% female.

As of the 2000 census, there were 30,136 people, 12,836 households, and 8,048 families residing in the city. The population density was 4,395.8/sq mi (1,697.2/km). There were 13,361 housing units at an average density of 1,948.9/sq mi (752.5/km). The racial makeup of the city was 93.66% White, 2.11% African American, 0.50% Native American, 1.67% Asian, 0.04% Pacific Islander, 0.85% from other races, and 1.18% from two or more races. Hispanic or Latino of any race were 3.98% of the population.

There were 12,836 households, out of which 26.7% had children under the age of 18 living with them, 49.2% were married couples living together, 9.7% had a female householder with no husband present, and 37.3% were non-families. 32.3% of all households were made up of individuals, and 14.1% had someone living alone who was 65 years of age or older. The average household size was 2.33 and the average family size was 2.98.

In the city, the population was spread out, with 21.5% under the age of 18, 8.3% from 18 to 24, 30.6% from 25 to 44, 23.3% from 45 to 64, and 16.2% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 93.0 males.

The median income for a household in the city was $46,927, and the median income for a family was $56,710. Males had a median income of $45,829 versus $28,549 for females. The per capita income for the city was $23,219. About 2.6% of families and 4.6% of the population were below the poverty line, including 3.4% of those under age 18 and 8.5% of those age 65 or over.

Southgate Community School District operates the following public schools:

• Anderson High School
• Davidson Middle School
• Allen Elementary
• Fordline Elementary
• Grogan Elementary
• North Pointe IB Elementary
• Shelters Elementary

• Christ the King Lutheran
• St. Pius X – opened September 1950
• Creative Montessori Academy