When was Penobscot County founded?

Penobscot County was founded in 1816, formed from Hancock County, and named after Penobscot Nation.

What is the county seat of Penobscot County?

The county seat of Penobscot County is Bangor.

Is there an online parcel map for Penobscot County?

Yes. Maine GeoLibrary (Maine Office of GIS) publishes a parcel map of 53,243 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Penobscot County's boundary or name changed?

Penobscot County was created in 1816 from Hancock County. Since then the Atlas of Historical County Boundaries records 18 later changes, chiefly involving Hancock County, Aroostook County and Somerset County.

Who issues building permits in Penobscot County?

The county's page on building permits: Entertainment Permits. Inside a city or town, ask that city first.

Is my lot in a flood zone?

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

County · code 23019

Penobscot CountyMaine

Penobscot County is a county in Maine, with its seat in Bangor, formed in 1816. The county was named after the Penobscot Nation.

Founded1816
County seatBangor
Named forPenobscot Nation
Land area3,397 sq mi + 160 sq mi water
Population152,199 2020 Census
Parcels mapped53,243 checked 16 October 2026

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

Updated 20 October 2026

Census outline · seat marked

Where it is

Penobscot on the map of Maine

Maine has 16 counties and county equivalents, each with its own records office. Shapes with a page are links.

Counties of Maine · Penobscot highlighted

History

Formed in 1816 from Hancock County

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

Penobscot County was created by Massachusetts from Hancock County in 1816. When Maine was admitted to the Union in 1820, Penobscot became a county of Maine. Over the following decades, the county gained territory from Somerset, Washington, and Hancock counties, and lost territory to the creation of Waldo, Piscataquis, and Aroostook counties.

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

1816
Penobscot County created Penobscot created by Massachusetts from Hancock.
from Hancock
15 February 1816 · Mass. Acts 1816, ch. 121, sec. 1/p. 156
1816
Gained territory Penobscot gained from Hancock when town of Hampden gained from town of Frankfurt and town of Orrington gained from town of Buckstown (now Bucksport).
from Hancock
17 June 1816 · Mass. Acts 1816, ch. 13, sec. 1/p. 195 and ch. 14/p. 196
1817
Gained territory Penobscot gained from Somerset.
from Somerset
14 June 1817 · Mass. Acts 1817, ch. 15/p. 398
1820
Became part of Maine Penobscot became a county in the state of Maine when Maine was separated from Massachusetts and admitted to the Union. 15 March 1820 · U.S. Stat., vol. 3, ch. 19 [1820]/p. 544
1827
Lost territory Penobscot lost to creation of Waldo.
to Waldo
3 July 1827 · Me. Pub. Acts 1827, ch. 354, sec. 1/p. 1109 and ch. 362/p. 1125

Show all 20 changes (15 more)

1816
Penobscot County created Penobscot created by Massachusetts from Hancock.
from Hancock
15 February 1816 · Mass. Acts 1816, ch. 121, sec. 1/p. 156
1816
Gained territory Penobscot gained from Hancock when town of Hampden gained from town of Frankfurt and town of Orrington gained from town of Buckstown (now Bucksport).
from Hancock
17 June 1816 · Mass. Acts 1816, ch. 13, sec. 1/p. 195 and ch. 14/p. 196
1817
Gained territory Penobscot gained from Somerset.
from Somerset
14 June 1817 · Mass. Acts 1817, ch. 15/p. 398
1820
Became part of Maine Penobscot became a county in the state of Maine when Maine was separated from Massachusetts and admitted to the Union. 15 March 1820 · U.S. Stat., vol. 3, ch. 19 [1820]/p. 544
1827
Lost territory Penobscot lost to creation of Waldo.
to Waldo
3 July 1827 · Me. Pub. Acts 1827, ch. 354, sec. 1/p. 1109 and ch. 362/p. 1125
1831
Gained territory Penobscot gained from Washington.
from Washington
15 March 1831 · Me. Priv. Acts 1831, ch. 151, sec. 2/p. 244
1833
Gained territory Penobscot gained from Somerset.
from Somerset
10 February 1833 · Me. Priv. Acts 1833, ch. 314/p. 488
1835
Gained territory Penobscot gained from Hancock.
from Hancock
10 March 1835 · Me. Priv. Acts 1835, ch. 559/p. 826
1838
Lost territory Penobscot lost to creation of Piscataquis.
to Piscataquis
30 April 1838 · Me. Pub. Acts 1838, ch. 353, sec. 1/p. 512
1839
Lost territory Penobscot lost to creation of Aroostook.
to Aroostook
1 May 1839 · Me. Pub. Acts 1839, ch. 395, sec. 1/p. 562
1841
Gained territory Penobscot gained from Hancock when town of Lowell gained from Page's Mill Settlement.
from Hancock
20 February 1841 · Me. Laws 1841, ch. 102/p. 296
1841
Gained territory Penobscot gained small area from Hancock when town of Brewer gained from towns of Bucksport and Dedham.
from Hancock
10 April 1841 · Me. Laws 1841, ch. 161/p. 357
1842
Changed Webster-Ashburton Treaty between Great Britain and the United States settled the U.S.-Canadian boundary, fixing the northern limits of Penobscot (no change).
U.s.
9 August 1842 · Van Zandt, 17-18
1843
Lost territory Penobscot lost to Aroostook.
to Aroostook
21 March 1843 · Me. Laws 1843, Priv., ch. 15/p. 51
1844
Exchanged territory By 29 February 1844, Penobscot exchanged with Somerset, placing county line along town boundaries.
with Somerset
29 February 1844 · Me. Laws 1844, Priv., ch. 148/p. 190
1844
Gained territory Penobscot gained from Washington and exchanged with Piscataquis.
from Washington from Piscataquis
12 March 1844 · Me. Laws 1844, Pub., ch. 99, secs. 1-5/pp. 92-94
1850
Gained territory Penobscot gained small area from Hancock when town of Orrington gained from town of Bucksport.
from Hancock
20 August 1850 · Me. Laws 1850, Priv., ch. 376, sec. 1/p. 519
1858
Gained territory Penobscot gained from Hancock.
from Hancock
15 March 1858 · Me. Laws 1858, Priv., ch. 198/p. 170
1889
Lost territory Penobscot lost to Aroostook when Reed Plantation gained from Drew Plantation.
to Aroostook
5 March 1889 · Me. Laws 1889, Priv., ch. 514/p. 874
1903
Gained territory Penobscot gained from Aroostook when Drew Plantation gained from Reed Plantation.
from Aroostook
28 March 1903 · Me. Laws 1903, Priv., ch. 364/p. 550

Land and parcels

What the maps cover in Penobscot

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

Parcels Good enough

Lot lines and tax-map numbers for 53,243 parcels from Maine GeoLibrary (Maine Office of GIS). Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 17 August 2026 · checked 16 October 2026
Address points Missing

No public address points layer found for Penobscot County yet.
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

Penobscot by the Census

Population

152,199 2020 Census count

Housing units

74,878 2020 Census count

Land area

3,397 square miles

Water area

160 square miles

People per sq mi

45 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

Who to ask before you build, dig or sell

Official county pages only. We link to them; we do not copy them, because they change.

In Maine, 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.

Records

Assessor and property records
Auto Registration
from penobscot-county.net · checked 13 October 2026
Clerk of court: deeds and plats
Register of Deeds
from penobscot-county.net · checked 13 October 2026

Permits

Entertainment Permitsfrom penobscot-county.net
Building Permitsfrom maine.gov

Zoning and code

Ordinancesfrom penobscot-county.net

County government

County government
The official website of Penobscot County.
penobscot-county.net

See your own lot on these maps

Open Penobscot 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 Penobscot County

When was Penobscot County founded?: Penobscot County was founded in 1816, formed from Hancock County, and named after Penobscot Nation.
What is the county seat of Penobscot County?: The county seat of Penobscot County is Bangor.
Is there an online parcel map for Penobscot County?: Yes. Maine GeoLibrary (Maine Office of GIS) publishes a parcel map of 53,243 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Penobscot County's boundary or name changed?: Penobscot County was created in 1816 from Hancock County. Since then the Atlas of Historical County Boundaries records 18 later changes, chiefly involving Hancock County, Aroostook County and Somerset County.
Who issues building permits in Penobscot County?: The county's page on building permits: Entertainment Permits. Inside a city or town, ask that city first.
Is my lot in a flood zone?: We do not have flood maps for Penobscot County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

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