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County · code 42005

Armstrong CountyPennsylvania

Armstrong County is a county in Pennsylvania with its seat in Kittanning. The county was created in 1800 from parts of Allegheny, Lycoming, and Westmoreland counties.

  • Founded1800
  • County seatKittanning
  • Named forJohn Armstrong
  • Land area653 sq mi + 11 sq mi water
  • Population65,558 2020 Census
  • Parcels mapped40,708 checked 16 October 2026
Open the free map Click any parcel in Armstrong County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated

ClarionIndianaButlerWestmorelandJeffersonAllegheny Kittanning Census outline · seat marked

Where it is

Armstrong on the map of Pennsylvania

Pennsylvania has 67 counties and county equivalents, each with its own records office. Shapes with a page are links.

Adams CountyAllegheny CountyBeaver CountyBedford CountyBerks CountyBlair CountyBradford CountyBucks CountyButler CountyCambria CountyCameron CountyCarbon CountyCentre CountyChester CountyClarion CountyClearfield CountyClinton CountyColumbia CountyCrawford CountyCumberland CountyDauphin CountyDelaware CountyElk CountyErie CountyFayette CountyForest CountyFranklin CountyFulton CountyGreene CountyHuntingdon CountyIndiana CountyJefferson CountyJuniata CountyLackawanna CountyLancaster CountyLawrence CountyLebanon CountyLehigh CountyLuzerne CountyLycoming CountyMcKean CountyMercer CountyMifflin CountyMonroe CountyMontgomery CountyMontour CountyNorthampton CountyNorthumberland CountyPerry CountyPhiladelphia CountyPike CountyPotter CountySchuylkill CountySnyder CountySomerset CountySullivan CountySusquehanna CountyTioga CountyUnion CountyVenango CountyWarren CountyWashington CountyWayne CountyWestmoreland CountyWyoming CountyYork CountyArmstrong County Armstrong
Counties of Pennsylvania · Armstrong highlighted

History

Formed in 1800 from Allegheny County, Lycoming County and Westmoreland County

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

Armstrong County was created on March 12, 1800, from Allegheny, Lycoming, and Westmoreland and was named after John Armstrong. Initially not fully organized, the county was attached to Westmoreland until it was fully organized and detached on November 4, 1805. In 1840, Armstrong lost land to the creation of Clarion County, and in 1864, it lost additional land to Butler County.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries.

  1. 1800
    Armstrong County created Armstrong created from Allegheny, Lycoming, and Westmoreland; not fully organized, attached to Westmoreland.
    from Alleghenyfrom Lycomingfrom Westmoreland
    · Pa. Stat., ch. 2130, pp. 459-460
  2. 1805
    Changed Armstrong fully organized, detached from Westmoreland.
    Westmoreland
    · Pa. Stat., ch. 2553, sec. 1/17:920
  3. 1840
    Boundary clarified Boundary between Armstrong and Westmoreland clarified (no change).
    with Westmorelandno change
    · Pa. Laws 1840, no. 73, sec. 1/p. 167
  4. 1840
    Lost territory Armstrong lost to the creation of Clarion.
    to Clarion
    · Pa. Laws 1838-1839, no. 27, secs. 1-2/pp. 51-52; Pa. Laws 1840, no. 165, secs. 1-3, 5/pp. 426-428
  5. 1864
    Lost territory Armstrong lost to Butler to accommodate local property owner.
    to Butler
    · Pa. Laws 1864, no. 721, sec. 1/p. 826

Land and parcels

What the maps cover in Armstrong

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

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

Armstrong by the Census

Population
65,558 2020 Census count
Housing units
32,106 2020 Census count
Land area
653 square miles
Water area
11 square miles
People per sq mi
100 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.

Inside a city or town, permits usually come from that city rather than the county.

Zoning and code

County government

See your own lot on these maps

Open Armstrong 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 Armstrong County

When was Armstrong County founded?
Armstrong County was founded in 1800, formed from Allegheny County, Lycoming County and Westmoreland County, and named after John Armstrong.
What is the county seat of Armstrong County?
The county seat of Armstrong County is Kittanning.
Is there an online parcel map for Armstrong County?
Yes. Armstrong County publishes a parcel map of 40,708 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Armstrong County's boundary or name changed?
Armstrong County was created in 1800 from Allegheny County, Lycoming County and Westmoreland County. Since then the Atlas of Historical County Boundaries records 3 later changes, chiefly involving Butler County, Clarion County and Westmoreland County.
Is my lot in a flood zone?
We do not have flood maps for Armstrong County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby

Counties next door