Mass. Gen. Laws ch. 34 § 3
Each county shall provide suitable jails, houses of correction, fireproof offices and other public buildings, including both the structures and the land upon which such structures are sited, necessary for its use; provided, however, that the county of Dukes need not provide a house of correction; provided, further, that the city of Boston shall provide necessary public buildings, including both the structures and the land upon which such structures are sited, for Suffolk county; provided, further, that the obligation to provide suitable structures of jails and houses of correction shall become that of the commonwealth and shall cease to be that of such counties or city in the event that the commonwealth constructs such facilities for such county or city; provided, further, that in any such county or city which has been ordered by a court to construct a new correctional facility, state assumption of the responsibility to provide such structure shall occur when the state appropriates funds therefor and such county or city has complied with any conditions attached to such appropriation, if any; and, provided further, that notwithstanding the fact that the commonwealth may have assumed the responsibilities of providing a suitable structure for such facilities, the counties and the city shall retain the obligation to provide for the operation and maintenance of such facilities. No courtroom of the superior court shall contain a cage for defendants.
Mass. Gen. Laws ch. 34, § 3