Boston is in the United States.
Boston ( pronounced [ ˈbɒstən ] ) is the capital and most populous city of the Commonwealth of Massachusetts in the United States . Boston 's many firsts include the United States ' first public school , Boston Latin School ( 1635 ) , first subway system , the Tremont Street Subway ( 1897 ) , and first public park , Boston Common ( 1634 ) . The city has one of the highest costs of living in the United States as it has undergone gentrification , though it remains high on world livability rankings .