August 2007

Download this layer


The MassGIS zoning datalayer represents the boundaries of municipal zoning districts. Because zoning is established at the town level, there is no standard district classification across the state. While districts in different towns may have similar or even identical names, their definitions are often quite different. Generalized codes have been added to make these data useful for regional display. A related table contains detailed information about the districts such as setbacks or text descriptions from each town’s zoning bylaws. Data are available for all communities. (Only primary district information is available for the City of Boston, not additional information for its bylaws.)

MassGIS stores the data in a statewide ArcSDE layer named ZONING_POLY. Data are distributed by town.

Zoning district boundaries change frequently and MassGIS currently has no formal process in place to regularly update these coverages.  These data should therefore be used for regional analysis only and not as official zoning maps.  The town’s own official zoning map and current copy of the by-law should be considered as the final word on zoning boundary questions or issues.


MassGIS received digital zoning data for every municipality in the Commonwealth (except Boston) as a deliverable from the statewide Buildout projects as supported by EOEEA's Community Preservation Initiative. Regional Planning  Agencies (RPAs) consulted with town officials and staff to derive zoning districts and their respective boundaries. In cases where data was incomplete, town bylaws were examined to fill in the gaps with either documented records or an educated guess. Primary attributes were provided with the data and further refined by MassGIS staff. Secondary attributes (i.e. linked tables) were created through extensive bylaws research by MassGIS staff and consultants.  The methods of boundary delineation and attribute population vary widely, as more than a dozen different RPAs provided data.  Furthermore, source materials such as assessor's maps and town databases contribute to a wide difference in original scales, types of attributes maintained, and relative accuracy of linework.  All data were subjected to a QA/QC procedure which attempted to standardize the information received, and enforce a certain minimum topological integrity.


The following items are included in the ZONING_POLY polygon attribute table (descriptions follow the item list): 
TOWN_ID 3 3 I - -
GEN_USE 1 1 I - GU
SOURCE 7 7 C - -
CURR_AS_OF 8 8 I - -
PRIM_USE2 2 2 C - -

A related Bylaws Table (found below) contains dimensional requirements for zoning districts.

ZONECODE is the district zoning code, a concatenation of town-ids and abbreviations from the town's original zoning maps. For example, a Residential A District in Weston (town-id 333) might be coded "333RES A" or "333RA" depending on what abbreviations the zoning map uses. If no abbreviations appear on the map then MassGIS assigned abbreviations to the districts.

PRIM_USE is a code used to generalize zoning districts into a statewide, standardized format.  The 21 codes listed below were assigned with the intent of capturing the highest density type of development permitted as a matter of right.  They are an aggregation of nearly every kind of zoning district encountered within the Commonwealth of Massachusetts' communities.  When considering which code to apply to a given town's district, the following criteria were used:

  1. The strict wording of permitted uses without regard for actual likelihood of a given type of development.
  2. The highest density permitted use is assigned regardless of the zoning district's nomenclature.  (i.e. an industrial use allowed within a district labeled as "Commercial".)
  3. Overlay districts, which generally add a level of restriction, are not taken into consideration.
  4. Only in cases where no uses are allowed as a matter of right (all uses require special permitting) does likelihood of a given use become considered.
The PRIM_USE categories assigned to each district were done so in an effort to allow comparison of similar types of allowed uses across town borders.  However, their assignment was still something of a subjective procedure.  Any analysis of regional zoning should be verified with an examination of bylaw tables of permitted uses, should disagreement with these codes arise.
Primary Use (PRIM_USE) codes:
CP - Conservation/Passive Recreation
R1 - Single Family Residential, >= 80,000 sq. ft. 
R2 - Single Family Residential, 40,000 - 79,999 sq. ft.
R3 - Single Family Residential, 20,000 - 39,999 sq. ft.
R4 - Single Family Residential, 15,000 - 19,999 sq. ft.
R5 - Single Family Residential, 5,000 - 14,999 sq. ft.
RA - Residential/Agricultural Mix 
ML - Multi-family, low density (3-8 D.U./acre)
MM - Multi-family, medium density (9-20 D.U./acre)
MH - Multi-family, high density (> 20 D.U./acre)
   (D.U. = dwelling units)
 MU - Mixed Use
IN - Institutional
HC - Health Care
OP - Office Park
HB - Highway Business
LB - Limited Business
GB - General Business
CB - Central Business
LI - Light Industrial
GI - General Industrial
NZ - Not Zoned

MassGIS has developed ArcView 3.x (.avl) avl format of zon_pu.avl
and ArcGIS 8.x (.lyr) lyr format of zon_pu.lyr
legend files which may be used to symbolize this layer on PRIM_USE or PRIM_USE2.

GEN_USE is a more generalized version of the PRIM_USE code. It further aggregates the 21 codes into 5 very basic categories as a means of displaying a coarse residential/commercial/industrial breakdown.

General Use (GEN_USE) codes:
1 - Residential (R1-R5,RA,ML,MM,MH)
2 - Commercial (OP,HB,LB,GB,CB)
3 - Industrial (LI,GI)
4 - Conservation (CP)
5 - Other (IN,HC,MU,NZ)

MassGIS has developed ArcView 3.x (.avl) avl format of zon_gu.avl
and ArcGIS 8.x (.lyr) lyr format of zon_gu.lyr
legend files which may be used to symbolize this layer on GEN_USE.

LASTEDITED is the date of latest editing of the digital data at MassGIS.  It is in numerical format (i.e. 20021002 for Oct. 2, 2002).

SOURCE is the source of either the digital spatial data, the attributes, or both.  Because multiple sources were used to generate this datalayer, certain discrepancies had to occasionally be resolved between the spatial information and the attribute tables.  When this was the case, the SOURCE field was populated with the identity of the attribute data provider.  Acceptable values for this field include TOWN (when the town provided most of the data and their own digital GIS layer), RPA (when a regional planning agency was acting on behalf of the town to produce a digital version of municipal zoning), the abbreviation of a specific Regional Planning Agency such as CMRPC, and B&T (initials representing the company Beals & Thomas which was contracted to provide bylaw attribute interpretations for many communities). The source for Boston's data is BRA (Boston Redevelopment Authority).

CURR_AS_OF is the date that a given community's bylaws were accepted for inclusion onto Munilaw, Inc.'s Munilaw zoning ordinance CD (June 2000 version), as listed within the CD. (Munilaw is an electronic publisher of zoning and subdivision laws on CD-ROM in Massachusetts, Connecticut, Rhode Island, New Hampshire and New York City.) If not given, then the latest date indicative of an approved amendment within the bylaws was used.  Also, if there was an update made to a town's zoning that was acquired during this datalayer's creation and it occurred after the date on the CD, the date when the change became known is used instead.  It is in the same numerical format as the LASTEDITED field.

PRIM_USE2 is the same as the PRIM_USE field in nearly all cases.  Any differences between the two represent a change made on behalf of the Buildout projects to reflect a more accurate "likelihood" of uses instead of a strict definition of "highest density use allowed by right".  It is a more subjective interpretation of the bylaws and was included to aid in cartographic representations.

Related Tables

The following two tables are found in the TOWN library's 'database' directory.

The "Bylaws Table" ZONING_POLY_BYLAWS is related by the ZONECODE field to the polygon attribute table on the ZONECODE item and contains detailed information about the districts such as setbacks or text descriptions. All the information associated with the Bylaws table was interpreted from digital copies of town bylaws as published by Munilaw Inc. on its June 2000 Munilaw CD product.


ZONEDIST 60/C A full descriptive name of the zoning district
CODE 10/C The district’s abbreviation from the zoning map/bylaws
ZONECODE 15/C A unique identifier for linking this table to the layer's polygon attribute table(s). It consists of a concatenation of the CODE value and the town ID.
PRIM_USE 2/C The regionalized zoning code classification based on the highest density use allowed by right
GEN_USE 1/I A more generalized version of the PRIM_USE code
PERM_USE 125/C A basic text description of the types of permitted uses allowed in a given district for a set of unique dimensional requirements
MINLOTSIZE 11/F The minimum lot size required. (sq. ft.)
DU_DENSITY 11/F Minimum lot area required per dwelling unit. (sq. ft.)
MAXHEIGHT 11/F Maximum building height. (ft.)
MXHT_XCEPT 125/C If maximum height varies according to town-specified criteria a text explanation is given here
MAXSTORIES 4/F Maximum number of building stories allowed
MXST_XCEPT 125/C If maximum number of stories varies according to town-specified criteria a text explanation given here
FAR 4/F Floor-area ratio
FAR_XCEPT 125/C If FAR varies according to town-specified criteria a text explanation given here
FRONTAGE 11/F Lot frontage. (ft.)
STBK1_TYPE 6/C Type of setback.  (e.g. "Front"; "Side"; or "Rear")
STBK1_BASE 4/F Standard setback of the given type. (ft.)
STBK1_MIN 4/F Minimum setback of the given type. (ft.)
STBK1_MAX 4/F Maximum setback of the given type. (ft.)
STBK2_TYPE 6/C Type of setback.  (e.g. "Front"; "Side"; or "Rear")
STBK2_BASE 4/F Standard setback of the given type. (ft.)
STBK2_MIN 4/F Minimum setback of the given type. (ft.)
STBK2_MAX 4/F Maximum setback of the given type. (ft.)
STBK3_TYPE 6/C Type of setback.  (e.g. "Front"; "Side"; or "Rear")
STBK3_BASE 4/F Standard setback of the given type. (ft.)
STBK3_MIN 4/F Minimum setback of the given type. (ft.)
STBK3_MAX 4/F Maximum setback of the given type. (ft.)
LOTCOV_MAX 11/F Percentage of lot occupancy allowed
LTCV_XCEPT 125/C If lot occupancy varies according to town-specified criteria a text explanation given here
COMMENTS 200/C General comments about the zoning district, permitted uses and dimensional requirements

Notes for bylaws table:
Values of "0" mean that the town addresses the issue, but does not specify a value/minimum-maximum for this zone.
Values of "999" are null values for numeric fields where no reference to the issue can be located within the town bylaws.
Values of "N/A" are null values for character fields where no reference to the issue can be located within the town bylaws.
Values of "-999" are reference values for numerical fields that use a formula (with no min./max. threshold given) to calculate a value and indicates that the reader should look at the COMMENTS field for the formula.
Bylaws data are not available for the City of Boston.

The "Status Table" ZONING_POLY_STATUS may be joined to the Towns polygon layer on the TOWN_ID field. The BYLAW_YR field contains the date for each town that its zoning bylaws were submitted to the Munilaw CD, as of June, 2000. Dates after June, 2000 represent the date that MassGIS received updated information directly from a town. The BYLAW_YR field is the most recent of all dates for a town, as taken from the CURR_AS_OF field in the polygon attribute table. Boston is coded as "0" (zero) since MassGIS does not have the city's bylaw information. In ArcSDE a spatial view named TOWNS_POLY_V_ZONING_BYLAW was created to store this relationship and is the basis for a status map that displays by town the most recent date that zoning bylaws were submitted to the Munilaw CD as of June, 2000, or the most recent update submitted to MassGIS if after June 2000.

Overlay Districts

Overlay districts are those which co-exist with "true" zoning districts by delineating them on top of the pre-existing districts. They are usually created to add specific regulations and restrictions based upon certain features or types of uses falling within their boundaries.  Some common examples are:  Floodplain areas, Adult Entertainment, Historic Districts, Aquifer and Water Protection areas, Wireless Communication uses, etc...  Generally, overlay district regulations supercede the restrictions of any underlying districts, though this is not always the case.  The most recent update of this datalayer did not generate a statewide coverage of overlay districts.  As production of overlay area delineation is completed, updates will be made and placed in an associated datalayer named OV.  MassGIS is no longer distributing the older "OV" layer, as it was incomplete and out-of-date. 


MassGIS maintains this data layer. While no formal mechanism for updates exists, town officials are encouraged to contact this office with any updates or potential errors found, along with formal documentation to support any proposed changes.  Please either send an email to with the subject "Zoning Update Request" or call (617) 626-4537. 

In January, 2003, two polygons were edited for data for Gloucester (town 107).

Data for Boston was added in March, 2004.

In August, 2007, data were updated for these 93 municipalities: Adams, Agawam, Amherst, Aquinnah, Ashburnham, Ashby, Athol, Ayer, Belchertown, Billerica, Bourne, Brewster, Chatham, Chelmsford, Cheshire, Chester, Chesterfield, Chicopee, Chilmark, Clarksburg, Clinton, Cummington, Dalton, Dennis,East Longmeadow, Edgartown, Egremont, Falmouth, Fitchburg, Gardner, Georgetown, Gosnold, Granby, Great Barrington, Groton, Hadley, Hampden, Harvard, Hatfield, Hubbardston, Huntington, Lancaster, Lanesborough, Lawrence, Lee, Lenox, Leominster, Lowell, Ludlow, Lunenburg, Mashpee, Monson, Monterey, New Ashford, North Adams, Northampton, Oak Bluffs, Otis, Palmer, Petersham, Phillipston, Pittsfield, Richmond, Rowley, Royalston, Russell, Salisbury, Sandisfield, Sheffield, Shirley, South Hadley, Southampton, Southwick, Sterling, Stockbridge, Templeton, Tisbury, Townsend, Truro, Ware, Washington, Wellfleet, West Springfield, West Stockbridge, West Tisbury, Westfield, Westminster, Wilbraham, Williamsburg, Williamstown, Winchendon, Worthington, and Yarmouth.

Last Updated 5/30/2013