Section 26C. The commission shall establish and maintain a state register of historic places, known as the state register. The state register shall contain the following properties: (1) all districts, sites, buildings, or objects determined eligible for listing or listed in the National Register of Historic Places; (2) all local historic districts established pursuant to chapter forty C or a special law; (3) all landmarks designated under local ordinance or by-law; (4) all structures and sites subject to a preservation easement approved or held by the commission pursuant to section thirty-two of chapter one hundred and eighty-four; (5) all historical or archeological landmarks certified pursuant to section twenty-seven and (6) all districts, structures, buildings, and sites listed in the state register of historic places pursuant to section twenty-six D.

The commission shall periodically update the state register.