St. Thomas' Church is an Episcopal church in a rural setting, located at Croom, Prince George's County, Maryland. It is one of four congregations that have constituted the parish of St. Thomas in the Episcopal Diocese of Washington, the others including the Church of the Atonement in Cheltenham, the Chapel of the Incarnation in Brandywine, and St. Simon's Mission also in Croom.

Croom is an unincorporated community and census-designated place in Southern Prince George's County, Maryland, United States. As of the 2020 census it had a population of 2,720. Croom largely consists of former tobacco farms and forests converted to Washington bedroom subdivisions such as nearby Marlton. The main part of Patuxent River Park is in Croom.