Baldwin is a borough in Allegheny County, Pennsylvania, United States.

Part of the Pittsburgh metropolitan area, the borough's population was 21,510 as of the 2020 census.

[5] A thin strip of land which is still part of Baldwin stretches north along Becks Run Road, separating St. Clair and Hays, reaching all the way to the Monongahela River.

It then forms the south bank of the river almost to the Glenwood Bridge, effectively surrounding Hays on three sides.

[7] Baldwin has eleven borders: Five with the Pittsburgh neighborhoods of Arlington and South Side Flats to the north, Hays to the northeast, Carrick to the west, and St. Clair to the north-northwest.

The remaining borders are: West Mifflin to the east, Pleasant Hills to the southeast, South Park Township to the south, Bethel Park to the southwest, and Whitehall and Brentwood to the west.

Agenda Meetings are held the second Tuesday of each month at 7:30 p.m. at the Municipal Building.