A building and loan association is a historical type of cooperative financial institution—often categorized alongside mutual savings and loan associations—established to pool members' savings deposits specifically to finance residential home mortgages. Historically organized as member-owned cooperative societies, these associations allowed working-class individuals to save money collectively and secure affordable housing loans. Over the 20th century, many building and loan associations evolved into modern savings and loan banks or merged into commercial banking institutions, expanding their consumer financial services while retaining their traditional focus on residential real estate lending.