[4] The city was established in 1948 but began to develop six years before it was granted the petition of incorporation.

Charles F. Vatterott, the developer and builder of most of the residential and commercial properties in St. Ann, started the community as a housing project for families of workers employed in nearby defense plants.

It was one of the few defense housing projects in the country to develop into a permanent town.

The original homesite was dedicated in honor of Saint Ann, the mother of the Virgin Mary.

Municipal neighbors to St. Ann are Bridgeton, Edmundson, Woodson Terrace, Breckenridge Hills, Overland, and a large portion of unincorporated St. Louis County that lies between Maryland Heights and Creve Coeur.

According to the United States Census Bureau, the city has a total area of 3.18 square miles (8.24 km2), all land.

[5] The 2020 United States census[7] counted 13,019 people, 5,711 households, and 3,344 families in St. Ann.

Of all households, 36.6% consisted of individuals and 16.1% had someone living alone who was 65 years of age or older.

St. Louis County Library operates the Rock Road Branch in St.

[10][11] Northwest Plaza, the largest enclosed shopping mall in Missouri, was located in St. Ann.

[12] Charter Communications leased 135,000SF of an old Macy's Department Store and renovated it into a call/technology center that employs over a 1,000 employees.

Parks & Recreation - The City maintains a 50,000 SF Community Center, 34-par, 9-hole golf course on 55 acres (220,000 m2) The city's six parks are Tiemeyer, Livingston & Wright, Buder, St. Ann, Schafer and Mary Ridge.

The Department is certified as a through the Commission on Accreditation for Law Enforcement Agencies (CALEA)[13] The Department provides 911 Dispatching Services through the North Central Dispatch Cooperative to multiple neighboring police agencies under contract.

North Central Dispatch is also certified through CALEA's Public Safety Communications Accreditation Program and is one of only two municipal police dispatch centers in the entire State of Missouri to be Certified through CALEA.