Mass. Gen. Laws ch. 184 § 33
Any city or town may file with the register of deeds for the county or district in which it is situated a map or set of maps of the city or town, to be known as the public restriction tract index, on which may be indexed conservation, preservation, agricultural preservation, watershed preservation and affordable housing restrictions and restrictions held by any governmental body. Such indexing shall indicate sufficiently for identification (a) the land subject to the restriction, (b) the name of the holder of the restriction, and (c) the place of record in the public records of the instrument imposing the restriction. Maps used by assessors to identify parcels taxed, and approximate boundaries without distances, shall be sufficient, and, where maps by parcels are not available, addition to other maps of approximate boundaries of restricted land shall be sufficient. If the names of the holders and the instrument references cannot be conveniently shown directly on the maps, they may be indicated by appropriate reference to accompanying lists. Such maps may also indicate similarly, so far as practicable, (a) any order or license issued by a governmental body entitled to be recorded or registered, (b) the approximate boundaries of any historic or architectural control district established under chapter forty C or any special act, ordinance or by-law where a certificate of appropriateness may be required for exterior changes, (c) any landmark certified by the Massachusetts historical commission pursuant to section twenty-seven of chapter nine, (d) any other land which any governmental body may own in fee, or in which it may hold any other interest, and (e) such additional data as the filing governmental body may deem appropriate.
Whenever any instrument of acquisition of a restriction or order or other appropriate evidence entitled to be indexed in a public restriction tract index is at the option of the holder of the right to enforce it submitted for such indexing, the register shall make, or require the holder of the right to enforce the restriction or order or interest to make, appropriate additions to the tract index.
The maps shall be in such form that they can be readily added to, changed, and reproduced, and shall be a public record, appropriately available for public inspection. If any governmental body, other than a city or town in which the land affected lies, holds a right to enforce a restriction or order or an interest entitled to be indexed in a public restriction tract index for any city or town which has not filed such an index, or if the secretary of environmental affairs or the Massachusetts historical commission or the commissioner of food and agriculture or the secretary of housing and livable communities approves a conservation or preservation restriction or agricultural or watershed preservation restriction or affordable housing restriction held by a charitable corporation or trust so entitled, and the city or town does not within one year after written request to the mayor or selectmen file a sufficient map or set of maps for the purpose, the holding governmental body or approving secretary, or commission may do so.
The registers of deeds, or a majority of them, may from time to time make and amend rules and regulations for administration of public restriction tract indexes, and the provisions of section thirteen A of chapter thirty-six shall not apply thereto. No such rule, regulation or any amendment thereof shall take effect until after it has been approved by the attorney general. New tract indexes may be filed, from time to time, upon compliance with such rules and regulations as may be necessary to assure against omission of prior additions and references still effective.
Mass. Gen. Laws ch. 184, § 184:33