Brattle Hall
 Brattle Hall is a historic building at 40 Brattle Street in Harvard Square Cambridge Massachusetts. The Colonial Revival building was constructed in 1889 for the Cambridge Social Union to a design by Longfellow Alden & Harlow. The Union was established as a social club in 1871 and moved into the adjacent William Brattle House in 1889. The hall was built to house the organization's library and to provide a space for larger meetings and social functions.