When was Suffolk County founded?

Suffolk County was founded in 1643, and named after Suffolk, England.

What is the county seat of Suffolk County?

The county seat of Suffolk County is Boston.

Is there an online parcel map for Suffolk County?

Yes. MassGIS (Bureau of Geographic Information), Commonwealth of Massachusetts publishes a parcel map of 121,032 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Suffolk County's boundary or name changed?

Suffolk County was created in 1643. Since then the Atlas of Historical County Boundaries records 35 later changes, most of them small boundary adjustments, chiefly involving Norfolk County, Middlesex County and Plymouth County.

Is my lot in a flood zone?

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

County · code 25025

Suffolk CountyMassachusetts

Suffolk County is in Massachusetts with its seat in Boston. It was established as one of four original counties in Massachusetts in 1643.

Founded1643
County seatBoston
Named forSuffolk, England
Land area58 sq mi + 62 sq mi water
Population797,936 2020 Census
Parcels mapped121,032 checked 15 October 2026

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

Updated 20 October 2026

Census outline · seat marked

Where it is

Suffolk 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 · Suffolk highlighted

History

Founded in 1643

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

Suffolk County was formed in 1643, and named after Suffolk, England. Boston is the county seat.

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

1643
Suffolk County created Suffolk created as one of four original counties in Massachusetts; Suffolk included territory in the northeast corner of present Rhode Island. 10 May 1643 · Mass. Recs., 2:38
1663
Lost territory Suffolk lost to Rhode Island Colony when King Charles Ii granted Rhode Island a charter as a self-governing corporate colony and defined its boundaries; Suffolk eliminated from Rhode Island.
to Ii
8 July 1663 · Bowen, Disputes, 33; Swindler, 8:368
1731
Lost territory Suffolk lost to creation of Worcester; Suffolk eliminated from Connecticut.
to Worcester
10 July 1731 · Mass. Col. Acts, vol. 2, ch. 8 [1730-1731], sec. 1/p. 584
1793
Lost territory Suffolk lost to creation of Norfolk.
to Norfolk
20 June 1793 · Mass. Acts 1793, ch. 43, sec. 1/p. 272 and ch. 9, sec. 1/p. 314
1803
Lost territory Suffolk lost towns of Hingham and Hull to Plymouth.
to Plymouth
18 June 1803 · Mass. Acts 1803, ch. 14, sec. 1/p. 246

Show all 40 changes (35 more, mostly small adjustments)

1643
Suffolk County created Suffolk created as one of four original counties in Massachusetts; Suffolk included territory in the northeast corner of present Rhode Island. 10 May 1643 · Mass. Recs., 2:38
1663
Lost territory Suffolk lost to Rhode Island Colony when King Charles Ii granted Rhode Island a charter as a self-governing corporate colony and defined its boundaries; Suffolk eliminated from Rhode Island.
to Ii
8 July 1663 · Bowen, Disputes, 33; Swindler, 8:368
c. 1664
Lost territory Suffolk lost to New Plymouth Colony when a joint commission from Massachusetts and Plymouth demarcated their mutual boundary ("Old Colony Line"). 31 May 1664 · Bradford, 427 n.
c. 1665
Gained territory Suffolk gained from Rhode Island Colony when royal commissioners set the provincial boundaries of Massachusetts, New Plymouth, and Rhode Island along the Blackstone River and the east side of Narragansett Bay, pending a conclusive royal decision. 27 February 1665 · Arnold, 1:315
c. 1690
Gained territory Suffolk gained non-county area in Connecticut when Massachusetts created the town of Woodstock. Woodstock lay almost entirely within present Connecticut, the result of uncertain geographical knowledge and disagreement over the line between the two colonies. 15 March 1690 · Bowen, Disputes, 53-58; Bowen, Woodstock, 1:31
1691
Changed Suffolk continued under the new Massachusetts Bay provincial charter issued by King William Iii and Queen Mary Ii (no change).
IiiIi
7 October 1691 · Mass. Col. Acts, vol. 1, ch. 27 [1692-1693], sec. 1/p. 63; Swindler, 5:80
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).
Bristol Plymouth
18 March 1712 · Mass. Col. Acts, vol. 21, ch. 152 [1711]/p. 799
1731
Lost territory Suffolk lost to creation of Worcester; Suffolk eliminated from Connecticut.
to Worcester
10 July 1731 · Mass. Col. Acts, vol. 2, ch. 8 [1730-1731], sec. 1/p. 584
c. 1747
Lost territory Suffolk lost to Providence (Rhode Island) when Rhode Island implemented the 1746 royal settlement of the boundary with Massachusetts; Suffolk eliminated from Rhode Island.
to Providence (R.I.)
17 February 1747 · Arnold, 2:157; R. I. Recs., 5:207-209
1770
Lost territory Suffolk lost small area to Plymouth when town of Bridgewater gained from town of Stoughton to accommodate local property owners.
to Plymouth
20 November 1770 · Mass. Col. Acts, vol. 5, ch. 15 [1770-1771], sec. 1/p. 116
1792
Boundary clarified Boundary between Suffolk and Middlesex was redefined in part when the boundary between towns of Medway and Sherburne was redefined (no change).
with Middlesexno change
3 March 1792 · Mass. Acts 1792, ch. 23, sec. 1/p. 155
1793
Lost territory Suffolk lost to creation of Norfolk.
to Norfolk
20 June 1793 · Mass. Acts 1793, ch. 43, sec. 1/p. 272 and ch. 9, sec. 1/p. 314
1803
Lost territory Suffolk lost towns of Hingham and Hull to Plymouth.
to Plymouth
18 June 1803 · Mass. Acts 1803, ch. 14, sec. 1/p. 246
1804
Gained territory Suffolk gained from Norfolk when Boston gained from Dorchester.
from Norfolk
6 March 1804 · Mass. Acts 1804, ch. 45, sec. 1/p. 412
1825
Changed Boundary between Suffolk and Norfolk was adjusted when the line between Boston and Brookline was adjusted.
Norfolk
22 February 1825 · Mass. Acts 1825, ch. 90/p. 73
1834
Gained territory Suffolk gained from Norfolk when Boston gained Thompson Island from Dorchester.
from Norfolk
25 March 1834 · Mass. Acts 1834, ch. 102/p. 129
1836
Boundary clarified Boundary between Suffolk and Norfolk was redefined when line between Boston and Roxbury was redefined.
with Norfolkno change
16 March 1836 · Mass. Acts 1836, ch. 37/p. 681
1837
Changed Boundary between Suffolk and Norfolk was adjusted slightly when line through water between Roxbury and Boston was adjusted.
Norfolk
19 April 1837 · Mass. Acts 1837, ch. 202, sec. 1/p. 222
1841
Lost territory Suffolk lost to Essex when town of Saugus gained from town of Chelsea.
to Essex
22 February 1841 · Mass. Acts 1841, ch. 30, sec. 1/p. 350
1850
Changed Boundary between Suffolk and Norfolk was adjusted when line through water between Boston and Roxbury was adjusted.
Norfolk
3 May 1850 · Mass. Acts 1850, ch. 281, sec. 1/p. 460
1855
Gained territory Suffolk gained small area from Norfolk when Boston gained from Dorchester.
from Norfolk
21 May 1855 · Mass. Acts 1855, ch. 468, sec. 1/p. 907
1860
Changed Boundary between Suffolk and Norfolk was adjusted slightly when line along streets between Boston and Roxbury was shifted to sides of streets from centerlines.
Norfolk
3 April 1860 · Mass. Acts 1860, ch. 172, sec. 1/p. 138
1868
Gained territory Suffolk gained from Norfolk when Boston gained all of Roxbury.
from Norfolk
6 January 1868 · Mass. Acts 1867, ch. 359, sec. 1/p. 754
1870
Gained territory Suffolk gained from Norfolk when Boston gained all of Dorchester.
from Norfolk
3 January 1870 · Mass. Acts 1869, ch. 349, sec. 1/p. 646
1870
Changed Boundary between Suffolk and Norfolk was adjusted slightly when line along streets between Boston and West Roxbury was shifted from one side to the other.
Norfolk
2 April 1870 · Mass. Acts 1870, ch. 146, sec. 1/pp. 21, 95
1870
Gained territory Suffolk gained small area from Norfolk when Boston gained from Brookline.
from Norfolk
18 June 1870 · Mass. Acts 1870, ch. 374, sec. 1/p. 290
1872
Gained territory Suffolk gained small area from Norfolk when Boston gained Mt. Hope Cemetery from town of West Roxbury.
from Norfolk
12 April 1872 · Mass. Acts 1872, ch. 197, sec. 1/p. 143
1872
Exchanged territory Suffolk exchanged small areas with Norfolk when Boston exchanged with Brookline.
with Norfolk
27 April 1872 · Mass. Acts 1872, ch. 267, sec. 1/p. 210
1874
Gained territory Suffolk gained from Middlesex and Norfolk when Boston gained all of Brighton, Charlestown, and West Roxbury.
from Middlesex from Norfolk
5 January 1874 · Mass. Acts 1873, ch. 286, sec. 1/p. 716, ch. 303, sec. 1/p. 747, and ch. 314, sec. 1/p. 810
1874
Gained territory Suffolk gained small area from Norfolk when Boston gained from Brookline.
from Norfolk
8 May 1874 · Mass. Acts 1874, ch. 220, sec. 1/p. 143
1874
Changed Boundary between Suffolk and Middlesex was adjusted when line between Boston and Newton was adjusted.
Middlesex
29 May 1874 · Mass. Acts 1874, ch. 277, sec. 1/p. 189
1875
Lost territory Suffolk lost small area to Middlesex when Newton gained from Boston.
to Middlesex
1 July 1875 · Mass. Acts 1875, ch. 184, sec. 1/p. 773
1890
Changed Boundary between Suffolk and Norfolk was adjusted when line between Boston and Brookline was adjusted.
Norfolk
27 May 1890 · Mass. Acts 1890, ch. 339, sec. 1/p. 299
1891
Changed Boundary between Suffolk and Middlesex was adjusted when line between Boston and Somerville was adjusted.
Middlesex
4 May 1891 · Mass. Acts 1891, ch. 294, sec. 1/p. 856
1894
Changed Boundary between Suffolk and Norfolk was adjusted slightly when line between northern Brookline and Boston was adjusted.
Norfolk
13 April 1894 · Mass. Acts 1894, ch. 242, sec. 1/p. 219
1898
Changed Boundary between Suffolk and Middlesex was adjusted when line through the Charles River between Boston and Cambridge was adjusted, and line between Boston and Newton was adjusted.
Middlesex
29 March 1898 · Mass. Acts 1898, ch. 242, sec. 1/p. 178 and ch. 243/p. 179
1898
Changed Boundary between Suffolk and Norfolk was adjusted when line between Boston and Hyde Park was adjusted.
Norfolk
1 April 1898 · Mass. Acts 1898, ch. 251, sec. 1/p. 185
1898
Changed Boundary between Suffolk and Middlesex was adjusted when line between Boston and Newton was adjusted.
Middlesex
13 May 1898 · Mass. Acts 1898, ch. 431, sec. 1/p. 376
1910
Changed Boundary between Suffolk and Middlesex was adjusted when line in the Charles River between Boston and Cambridge was adjusted.
Middlesex
29 March 1910 · Mass. Acts 1910, ch. 312, sec. 1/p. 239
1912
Gained territory Suffolk gained from Norfolk when Boston gained all of Hyde Park.
from Norfolk
1 January 1912 · Mass. Acts 1911, ch. 469, sec. 1/p. 450 and ch. 583, sec. 1/p. 600

Land and parcels

What the maps cover in Suffolk

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

Parcels Good enough

Lot lines and tax-map numbers for 121,032 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, 510,535 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

Suffolk by the Census

Population

797,936 2020 Census count

Housing units

349,616 2020 Census count

Land area

58 square miles

Water area

62 square miles · 52% of the county, including large bodies of water

People per sq mi

13,698 population ÷ land area

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

See your own lot on these maps

Open Suffolk 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 Suffolk County

When was Suffolk County founded?: Suffolk County was founded in 1643, and named after Suffolk, England.
What is the county seat of Suffolk County?: The county seat of Suffolk County is Boston.
Is there an online parcel map for Suffolk County?: Yes. MassGIS (Bureau of Geographic Information), Commonwealth of Massachusetts publishes a parcel map of 121,032 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Suffolk County's boundary or name changed?: Suffolk County was created in 1643. Since then the Atlas of Historical County Boundaries records 35 later changes, most of them small boundary adjustments, chiefly involving Norfolk County, Middlesex County and Plymouth County.
Is my lot in a flood zone?: We do not have flood maps for Suffolk County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby