The U.S. Post Office (now known as the Woonsocket YMCA) is a historic former post office building at 295 Main Street in Woonsocket, Rhode Island. The single-story masonry building was built 1910-12 and served as Woonsocket's main post office until 1975. The building was added to the National Register of Historic Places in 1979. It is now part of the Woonsocket YMCA.