What is the county seat of Worcester County?

The county seat of Worcester County is Worcester.

Is there an online parcel map for Worcester County?

Not that we have found yet. Lot lines and owners of record are kept by the county assessor's office. When a public parcel map appears, it shows here.

Has Worcester County's boundary or name changed?

Worcester County was created in 1731 from Hampshire County, Middlesex County and Suffolk County. Since then the Atlas of Historical County Boundaries records 31 later changes, most of them small boundary adjustments, chiefly involving Middlesex County, Hampshire County and Franklin County.

Is my lot in a flood zone?

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

County · code 25027

Worcester CountyMassachusetts

Worcester County is in Massachusetts and has its seat in Worcester. The county was created on July 10, 1731, from parts of Hampshire, Middlesex, and Suffolk counties.

Founded1731
County seatWorcester
Named forWorcester, Massachusetts
Land area1,511 sq mi + 68 sq mi water
Population862,111 2020 Census

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

Updated 20 October 2026

Census outline · seat marked

Where it is

Worcester 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 · Worcester highlighted

History

Formed in 1731 from Hampshire County, Middlesex County and Suffolk County

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

When Worcester County was created in 1731, it initially included the town of Woodstock in Connecticut, but lost that area to Connecticut in 1749. Between 1732 and 1767, Worcester County's boundaries were adjusted through the creation of new towns and exchanges with neighboring Hampshire and Middlesex counties.

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

1731
Worcester County created Worcester created from Hampshire, Middlesex, and Suffolk; Worcester included the town of Woodstock in Connecticut.
from Hampshire from Middlesex from Suffolk
10 July 1731 · Mass. Col. Acts, vol. 2, ch. 8 [1730-1731], sec. 1/p. 584
1732
Exchanged territory Worcester exchanged with Middlesex when town of Harvard was created from towns of Groton, Lancaster, and Stow.
with Middlesex
29 June 1732 · Mass. Col. Acts, vol. 2, ch. 4 [1732-1733], sec. 1/p. 644
1749
Lost territory In May 1749, Worcester lost town of Woodstock to Connecticut when Connecticut responded to Woodstock's request for annexation and extended jurisdiction over the area south of the 1713 provincial line; Worcester eliminated from Connecticut. 31 May 1749 · Bowen, Disputes, 62; Hooker, 22, 26
1783
Lost territory Worcester lost to Middlesex when town of Boxborough gained from town of Harvard.
to Middlesex
25 February 1783 · Mass. Acts 1783, ch. 8, sec. 1/p. 214
1783
Lost territory Worcester lost to Hampshire when town of Orange was created from towns of Athol and Royalston.
to Hampshire
15 October 1783 · Mass. Acts 1783, ch. 2, sec. 1/p. 38

Show all 41 changes (36 more, mostly small adjustments)

1731
Worcester County created Worcester created from Hampshire, Middlesex, and Suffolk; Worcester included the town of Woodstock in Connecticut.
from Hampshire from Middlesex from Suffolk
10 July 1731 · Mass. Col. Acts, vol. 2, ch. 8 [1730-1731], sec. 1/p. 584
1732
Exchanged territory Worcester exchanged with Middlesex when town of Harvard was created from towns of Groton, Lancaster, and Stow.
with Middlesex
29 June 1732 · Mass. Col. Acts, vol. 2, ch. 4 [1732-1733], sec. 1/p. 644
1735
Gained territory Worcester gained small area from Middlesex when town of Upton was created from town of Hopkinton.
from Middlesex
14 June 1735 · Mass. Col. Acts, vol. 2, ch. 11 [1735-1736], sec. 1/p. 764
c. 1742
Gained territory Worcester gained from Hampshire when town of Western (now Warren) was created from towns of Brookfield, Brimfield, and Kingsfield.
from Hampshire
16 January 1742 · Mass. Col. Acts, vol. 2, ch. 17 [1741-1742], sec. 2/p. 1088
1749
Lost territory In May 1749, Worcester lost town of Woodstock to Connecticut when Connecticut responded to Woodstock's request for annexation and extended jurisdiction over the area south of the 1713 provincial line; Worcester eliminated from Connecticut. 31 May 1749 · Bowen, Disputes, 62; Hooker, 22, 26
1753
Boundary clarified Worcester boundaries were redefined to cover all adjacent territory not already specifically part of another county (no change).
no change
12 April 1753 · Mass. Col. Acts, vol. 3, ch. 27 [1752-1753]/p. 656
1756
Changed Boundary between Worcester and Hampshire was adjusted when the dispute between the towns of Greenwich (extinct) and Hardwick was settled (no change).
Hampshire
9 June 1756 · Mass. Col. Acts, vol. 15, ch. 51 [1756-1757]/p. 550
1764
Gained territory Worcester gained small area from Hampshire when town of Western (now Warren) gained from town of Palmer.
from Hampshire
5 January 1764 · Mass. Col. Acts, vol. 17, ch. 14 [1764-1765]/p. 516
1765
Lost territory Worcester lost small area to Hampshire when town of Greenwich (extinct) gained from town of Hardwick.
to Hampshire
5 February 1765 · Mass. Col. Acts, vol. 17, ch. 218 [1764-1765]/p. 603
1767
Lost territory Worcester lost small area to Middlesex when town of Ashby was created from towns of Fitchburg and Ashburnham.
to Middlesex
6 March 1767 · Mass. Col. Acts, vol. 4, ch. 15 [1766-1767]/p. 908
1783
Lost territory Worcester lost to Middlesex when town of Boxborough gained from town of Harvard.
to Middlesex
25 February 1783 · Mass. Acts 1783, ch. 8, sec. 1/p. 214
1783
Lost territory Worcester lost to Hampshire when town of Orange was created from towns of Athol and Royalston.
to Hampshire
15 October 1783 · Mass. Acts 1783, ch. 2, sec. 1/p. 38
1784
Gained territory Worcester gained small area from Middlesex when town of Berlin was created from towns of Marlborough, Northborough, and Bolton.
from Middlesex
16 March 1784 · Mass. Acts 1784, ch. 23, sec. 1/p. 98
1786
Gained territory Worcester gained small area from Middlesex when town of Southborough gained from town of Framingham.
from Middlesex
7 March 1786 · Mass. Acts 1786, ch. 21, sec. 1/p. 410
1792
Lost territory Worcester lost to Middlesex when town of Ashby gained from town of Ashburnham.
to Middlesex
16 November 1792 · Mass. Acts 1792, ch. 2, sec. 1/p. 224
1794
Gained territory Worcester gained small area from Hampshire when town of Western (now Warren) gained from town of Palmer to accommodate local property owners.
from Hampshire
15 July 1794 · Temple, 10
1801
Gained territory Worcester gained from Hampshire when town of Dana (extinct) was created from towns of Greenwich (extinct), Hardwick, and Petersham.
from Hampshire
18 February 1801 · Mass. Acts 1801, ch. 14, sec. 1/p. 453
1807
Gained territory Worcester gained small area from Middlesex when town of Northborough gained from town of Marlborough.
from Middlesex
20 June 1807 · Mass. Acts 1807, p. 52
1808
Gained territory Worcester gained small area from Middlesex when town of Upton gained from town of Hopkinton to accommodate local property owner.
from Middlesex
8 March 1808 · Mass. Acts 1808, ch. 106, sec. 1/p. 336
1816
Gained territory Worcester gained small area from Franklin when town of Athol gained from town of Orange.
from Franklin
7 February 1816 · Mass. Acts 1816, ch. 62/p. 71
1823
Lost territory Worcester lost small area to Hampshire when town of Ware gained from town of Western (now Warren).
to Hampshire
8 February 1823 · Mass. Acts 1823, ch. 76/p. 114
1826
Exchanged territory Worcester exchanged narrow strips with Tolland (Connecticut) and Windham (Connecticut) when an irregularity in the state boundary was straightened.
with Tolland (Conn.)with Windham (Conn.)
3 November 1826 · Bowen, Disputes, 66; Hooker, 28
1829
Gained territory Worcester gained small area (one acre) from Middlesex when town of Bolton gained from town of Marlborough to accommodate local property owner.
from Middlesex
11 February 1829 · Mass. Acts 1829, ch. 47/p. 72
1829
Lost territory Worcester lost small area to Middlesex when town of Ashby gained from town of Fitchburg to accommodate local property owner.
to Middlesex
3 March 1829 · Mass. Acts 1829, ch. 125/p. 200 and ch. 133/p. 209
1830
Gained territory Worcester gained small area from Franklin when town of Athol gained from town of New Salem.
from Franklin
5 February 1830 · Mass. Acts 1830, ch. 33/p. 300
1831
Lost territory Worcester lost small area to Hampden when town of Palmer gained from town of Western (now Warren).
to Hampden
7 February 1831 · Mass. Acts 1831, ch. 37/p. 545
1835
Exchanged territory Worcester exchanged with Middlesex when towns of Holliston, Hopkinton, and Milford exchanged territory.
with Middlesex
27 March 1835 · Mass. Acts 1835, ch. 72/p. 382
1837
Gained territory Worcester gained from Franklin when town of Athol gained from town of New Salem.
from Franklin
16 March 1837 · Mass. Acts 1837, ch. 80, sec. 1/p. 70
1838
Boundary clarified Boundary between Worcester and Middlesex was redefined in part when line between towns of Marlborough and Bolton was redefined (no change).
with Middlesexno change
16 March 1838 · Mass. Acts 1838, ch. 36/p. 330
1843
Lost territory Worcester lost small area to Middlesex when town of Marlborough gained from town of Southborough to accommodate local property owners.
to Middlesex
24 March 1843 · Mass. Acts 1843, ch. 89, sec. 1/p. 53
1846
Boundary clarified Boundary between Worcester and Middlesex was redefined in part when line between towns of Shirley and Lunenburg was redefined (no change).
with Middlesexno change
3 March 1846 · Mass. Acts 1846, ch. 74/p. 35
1848
Boundary clarified Boundary between Worcester and Middlesex was redefined in part when line between towns of Shirley and Lunenburg was redefined (no change).
with Middlesexno change
25 April 1848 · Mass. Acts 1848, ch. 194, sec. 1/p. 708
1859
Gained territory Worcester gained small area from Middlesex when town of Milford gained from town of Holliston.
from Middlesex
1 April 1859 · Mass. Acts 1859, ch. 149/p. 312
1868
Lost territory Worcester lost to Middlesex when town of Hudson gained from town of Bolton.
to Middlesex
20 March 1868 · Mass. Acts 1868, ch. 79, sec. 1/p. 62
1872
Exchanged territory Worcester exchanged small areas with Norfolk when town of Bellingham exchanged with town of Mendon.
with Norfolk
7 March 1872 · Mass. Acts 1872, ch. 69, sec. 1/p. 57
1901
Boundary clarified Boundary between Worcester and Middlesex was redefined when line between towns of Marlborough and Southborough was redefined (no change).
with Middlesexno change
16 May 1901 · Mass. Acts 1901, ch. 393, sec. 1/p. 306
1905
Boundary clarified Boundary between Worcester and Middlesex was redefined in part when line between towns of Berlin and Hudson was redefined (no change), and when line between towns of Marlborough and Berlin was adjusted.
with Middlesexno change
1 May 1905 · Mass. Acts 1905, ch. 357, sec. 1/p. 283 and ch. 358, sec. 1/p. 284
1906
Lost territory Worcester lost small area to Middlesex when towns of Boxborough and Littleton gained from town of Harvard.
to Middlesex
14 June 1906 · Mass. Acts 1906, ch. 483, sec. 1/p. 654 and ch. 484, sec. 1/p. 655
1907
Boundary clarified Boundary between Worcester and Middlesex was redefined in part when town of Hopkinton's boundary with towns of Milford and Upton was redefined (no change).
with Middlesexno change
16 May 1907 · Mass. Acts 1907, ch. 423, sec. 1 and ch. 424, sec. 1/pp. 362-363
1911
Boundary clarified Boundary between Worcester and Franklin was redefined in part when line between towns of New Salem and Prescott (extinct) was redefined (no change).
with Franklinno change
27 April 1911 · Mass. Acts 1911, ch. 340, sec. 1/p. 310
1938
Gained territory Worcester gained from Hampshire when town of Petersham gained from towns of Dana, Greenwich, and Prescott, and town of Hardwick gained from Greenwich. Dana, Greenwich, and Prescott were disincorporated when Quabbin Reservoir was created in the Swift River Valley.
from Hampshire
28 April 1938 · Mass. Acts 1927, ch. 321, sec. 1/p. 384; Mass. Acts 1938, ch. 240, sec. 1/p. 188; Mass. Sec. Comm., 48

Land and parcels

What the maps cover in Worcester

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

Parcels Missing

No public parcel map found for Worcester County yet. Lot lines and owners of record are kept by the county assessor's office.
Address points Official

One point per address, 426,442 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

Worcester by the Census

Population

862,111 2020 Census count

Housing units

351,764 2020 Census count

Land area

1,511 square miles

Water area

68 square miles

People per sq mi

571 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 Worcester 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.

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Questions

Common questions about Worcester County

When was Worcester County founded?: Worcester County was founded in 1731, formed from Hampshire County, Middlesex County and Suffolk County, and named after Worcester, Massachusetts.
What is the county seat of Worcester County?: The county seat of Worcester County is Worcester.
Is there an online parcel map for Worcester County?: Not that we have found yet. Lot lines and owners of record are kept by the county assessor's office. When a public parcel map appears, it shows here.
Has Worcester County's boundary or name changed?: Worcester County was created in 1731 from Hampshire County, Middlesex County and Suffolk County. Since then the Atlas of Historical County Boundaries records 31 later changes, most of them small boundary adjustments, chiefly involving Middlesex County, Hampshire County and Franklin County.
Is my lot in a flood zone?: We do not have flood maps for Worcester County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby