The inventory is then submitted to the State, which assumes a protective function if historic properties are threatened. The inventory also helps the State evaluate properties when they are submitted to the National Register of Historic Places. When an area containing several structures of historic value is identified, the commission may set up a historic district study committee, its members appointed by the selectmen. Following a poll of residents in the proposed district and a public hearing, a historic district is established by a two-thirds vote of town meeting. From that time forward, any changes in the exterior design of the buildings within the district must be considered and approved by a district commission.
Property owners have the right of appeal.
Approval may be given, subject to conditions or restrictions. Beginning in 1972, Island towns adopted comprehensive zoning bylaws, which are presently in place in all towns. They regulate the size of lots and the density permitted, the siting and the height of the structures. The selectmen or building and zoning officers of the towns administer the bylaws, issuing permits for all construction. Cases involving Developments of Regional Impact are referred to the Martha's Vineyard Commission.