When was Plymouth County founded?

Plymouth County was founded in 1685, and named after Plymouth, Massachusetts.

What is the county seat of Plymouth County?

The county seat of Plymouth County is Plymouth.

Is there an online parcel map for Plymouth County?

Yes. MassGIS (Bureau of Geographic Information), Commonwealth of Massachusetts publishes a parcel map of 198,967 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Plymouth County's boundary or name changed?

Plymouth County was created in 1685. Since then the Atlas of Historical County Boundaries records 7 later changes, most of them small boundary adjustments, chiefly involving Norfolk County, Suffolk County and Barnstable County.

Is my lot in a flood zone?

We do not have flood maps for Plymouth County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

County · code 25023

Plymouth CountyMassachusetts

Plymouth County is a county in Massachusetts with its seat in Plymouth, formed in 1685 as one of the three original counties in New Plymouth Colony.

Founded1685
County seatPlymouth
Named forPlymouth, Massachusetts
Land area659 sq mi + 435 sq mi water
Population530,819 2020 Census
Parcels mapped198,967 checked 15 October 2026

Open the free map Click any parcel in Plymouth County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated 19 October 2026

Census outline · seat marked

Where it is

Plymouth on the map of Massachusetts

Massachusetts has 14 counties and county equivalents, each with its own records office. Shapes with a page are links.

Counties of Massachusetts · Plymouth highlighted

History

Founded in 1685

An old deed may name a county that no longer exists, or a boundary that has since moved.

Plymouth was created on June 2, 1685, as one of three original counties in New Plymouth Colony. When Massachusetts Bay absorbed New Plymouth Colony under the provincial charter of King William Iii and Queen Mary II in 1691, Plymouth continued as a county. Throughout the 18th and 19th centuries, Plymouth adjusted its boundaries with neighboring counties, gaining towns including Rochester from Barnstable County (1707), Hingham and Hull from Suffolk County (1803), and small areas from Norfolk and Suffolk counties.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries; the 5 that matter most are shown first.

1685
Plymouth County created Plymouth created as one of three original counties in New Plymouth Colony. 2 June 1685 · Ply. Laws, ch. 6/p. 19
1707
Gained territory Plymouth gained town of Rochester from Barnstable.
from Barnstable
19 November 1707 · Mass. Col. Acts, vol. 21, ch. 60 [1707]/p. 755
1708
Gained territory Plymouth gained small non-county area between Bristol and Plymouth.
from Bristol
29 October 1708 · Mass. Col. Acts, vol. 21, ch. 76 [1708]/p. 767
1770
Gained territory Plymouth gained small area from Suffolk when town of Bridgewater gained from town of Stoughton to accommodate local property owners.
from Suffolk
20 November 1770 · Mass. Col. Acts, vol. 5, ch. 15 [1770-1771], sec. 1/p. 116
1803
Gained territory Plymouth gained towns of Hingham and Hull from Suffolk.
from Suffolk
18 June 1803 · Mass. Acts 1803, ch. 14, sec. 1/p. 246

Show all 17 changes (12 more, mostly small adjustments)

1685
Plymouth County created Plymouth created as one of three original counties in New Plymouth Colony. 2 June 1685 · Ply. Laws, ch. 6/p. 19
1691
Changed Plymouth continued under the new Massachusetts Bay provincial charter issued by King William Iii and Queen Mary Ii; Massachusetts Bay absorbed New Plymouth Colony (no change).
IiiIi
7 October 1691 · Mass. Col. Acts, vol. 1, ch. 27 [1692-1693], sec. 1/p. 63; Swindler, 5:80
1707
Gained territory Plymouth gained town of Rochester from Barnstable.
from Barnstable
19 November 1707 · Mass. Col. Acts, vol. 21, ch. 60 [1707]/p. 755
1708
Gained territory Plymouth gained small non-county area between Bristol and Plymouth.
from Bristol
29 October 1708 · Mass. Col. Acts, vol. 21, ch. 76 [1708]/p. 767
c. 1712
Changed The "Old Colony Line" that divided Massachusetts and New Plymouth when they were separate colonies was declared the boundary separating Suffolk from Bristol and Plymouth (no change).
Suffolk Bristol
18 March 1712 · Mass. Col. Acts, vol. 21, ch. 152 [1711]/p. 799
1770
Gained territory Plymouth gained small area from Suffolk when town of Bridgewater gained from town of Stoughton to accommodate local property owners.
from Suffolk
20 November 1770 · Mass. Col. Acts, vol. 5, ch. 15 [1770-1771], sec. 1/p. 116
1798
Gained territory Plymouth gained small strip from Norfolk when town of Bridgewater gained from town of Stoughton.
from Norfolk
8 February 1798 · Mass. Acts 1798, ch. 10, sec. 1/p. 164
1803
Gained territory Plymouth gained towns of Hingham and Hull from Suffolk.
from Suffolk
18 June 1803 · Mass. Acts 1803, ch. 14, sec. 1/p. 246
1823
Lost territory Plymouth lost small area to Norfolk when town of Cohasset gained from town of Scituate to accommodate local property owners.
to Norfolk
14 June 1823 · Mass. Acts 1823, ch. 28/p. 237
1836
Boundary clarified Boundary between Plymouth and Bristol was redefined in part when line between towns of Rochester and Fairhaven was redefined (no change).
with Bristolno change
9 April 1836 · Mass. Acts 1836, ch. 193, sec. 1/p. 876
1840
Gained territory Plymouth gained small area from Norfolk when town of Scituate gained from town of Cohasset to accommodate local property owner.
from Norfolk
20 March 1840 · Mass. Acts 1840, ch. 58, sec. 1/p. 206
1847
Boundary clarified Boundary between Plymouth and Norfolk was clarified in part when line between towns of Weymouth and Abington was clarified (no change).
with Norfolkno change
31 March 1847 · Mass. Acts 1847, ch. 138/p. 391
1861
Boundary clarified Boundary between Plymouth and Norfolk was clarified in part when boundary between towns of Abington and Randolph was clarified (no change).
with Norfolkno change
21 March 1861 · Mass. Acts 1861, ch. 86/p. 390
1867
Boundary clarified Boundary between Plymouth and Bristol was clarified in part when boundary between towns of Lakeville and Taunton was clarified (no change).
with Bristolno change
1 June 1867 · Mass. Acts 1867, ch. 352, sec. 1/p. 745
1897
Boundary clarified Boundary between Plymouth and Barnstable was clarified in part when line between towns of Wareham and Bourne was clarified (no change).
with Barnstableno change
14 April 1897 · Mass. Acts 1897, ch. 281, sec. 1/p. 258
1897
Changed Boundary between Plymouth and Norfolk was adjusted when line between towns of Cohasset and Hingham was adjusted (no change).
Norfolk
30 April 1897 · Mass. Acts 1897, ch. 330, sec. 1/p. 318
1928
Changed Boundary between Plymouth and Norfolk was adjusted when line between towns of Hingham and Cohasset was adjusted (no change).
Norfolk
23 March 1928 · Mass. Acts 1928, ch. 160, sec. 1/p. 184

Land and parcels

What the maps cover in Plymouth

Who publishes each layer, how good it is, and when we last checked.

Parcels Good enough

Lot lines and tax-map numbers for 198,967 parcels from MassGIS (Bureau of Geographic Information), Commonwealth of Massachusetts. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 15 October 2026
Address points Official

One point per address, 255,029 in all from MassGIS.
checked 14 October 2026
Buildings Reference

Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026

Official: from the office that keeps the record
Good enough: a reliable statewide or national copy
Fallback: a guide only; check the official record
Missing: nothing public found yet

People and land

Plymouth by the Census

Population

530,819 2020 Census count

Housing units

214,770 2020 Census count

Land area

659 square miles

Water area

435 square miles · 40% of the county, including large bodies of water

People per sq mi

806 population ÷ land area

Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.

Rules and offices

Plymouth County's official site

We have found the county's site but not its offices yet; start there.

In Massachusetts, permits, zoning and assessing are handled by each city or town, not the county, and deeds are recorded at the county's registry of deeds (search the registries).

County government

County government
The official website of Plymouth County.
plymouthcounty-ma.gov

See your own lot on these maps

Open Plymouth County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.

Open the free map no sign-in Pro early access

Questions

Common questions about Plymouth County

When was Plymouth County founded?: Plymouth County was founded in 1685, and named after Plymouth, Massachusetts.
What is the county seat of Plymouth County?: The county seat of Plymouth County is Plymouth.
Is there an online parcel map for Plymouth County?: Yes. MassGIS (Bureau of Geographic Information), Commonwealth of Massachusetts publishes a parcel map of 198,967 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Plymouth County's boundary or name changed?: Plymouth County was created in 1685. Since then the Atlas of Historical County Boundaries records 7 later changes, most of them small boundary adjustments, chiefly involving Norfolk County, Suffolk County and Barnstable County.
Is my lot in a flood zone?: We do not have flood maps for Plymouth County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby