The Depot Street slab bridge is one of three bridges on Depot Street that pass through the floodplain of the Contoocook River. It serves as a flood relief structure when the river overflows its banks. The existing bridge, built in 1947, was a 25-foot span, cast-in-place, reinforced, concrete deck founded on mortared rubble masonry abutments. The bridge was severely deteriorated, posted for 15 tons, and was on the NHDOT’s Municipal Redlist. The replacement bridge structure has a span of approximately 37 feet. The superstructure consists of solid prestressed concrete butted deck beams supported on steel H-piles with cast-in-place concrete pile caps. This project was funded by the Town of Antrim and the New Hampshire Department of Transportation (NHDOT) through the Municipally Managed Bridge Aid Program.