Montgomery County, colloquially referred to as Montco, is in the Commonwealth of Pennsylvania. As of the 2020 census, the population of the county was 856,553, making it the third-most populous county in Pennsylvania after Philadelphia and Allegheny counties and the most populous county in Pennsylvania without a major city.
The county seat and largest city is Norristown. The county is part of the PhiladelphiaâÂÂCamdenâÂÂWilmington PA-NJâÂÂDEâÂÂMD metropolitan statistical area, known as the Delaware Valley, and marks the Delaware Valley's northern border with the Lehigh Valley region of eastern Pennsylvania.
The county borders Philadelphia, the nation's sixth-largest city, to its southeast, Bucks County to its east, Berks and Lehigh counties to its north, Delaware County to its south, and Chester County to its southwest.
The county was created on September 10, 1784, out of land originally part of Philadelphia County. The first courthouse was housed in Barley Sheaf Inn. The county is named after Richard Montgomery, an American Revolutionary War general killed on December 31, 1775 while attempting to capture Quebec City.
According to the U.S. Census Bureau, the county has a total area of , of which was land and (0.9%) of which was water.
As of the 2020 census, the county had a population of 856,553 and a median age of 41.4 years. 21.3% of residents were under the age of 18 and 18.7% of residents were 65 years of age or older. For every 100 females there were 94.4 males, and for every 100 females age 18 and over there were 91.7 males age 18 and over.
The racial makeup of the county was 73.3% White (72.2% White, non-Hispanic), 9.5% Black or African American, 0.2% American Indian and Alaska Native, 7.9% Asian, <0.1% Native Hawaiian and Pacific Islander, 2.9% from some other race, and 6.1% from two or more races. Hispanic or Latino residents of any race comprised 6.4% of the population.
96.7% of residents lived in urban areas, while 3.3% lived in rural areas.
There were 328,958 households in the county, of which 30.2% had children under the age of 18 living in them. Of all households, 53.0% were married-couple households, 15.6% were households with a male householder and no spouse or partner present, and 25.6% were households with a female householder and no spouse or partner present. About 26.6% of all households were made up of individuals and 12.2% had someone living alone who was 65 years of age or older.
There were 346,877 housing units, of which 5.2% were vacant. Among occupied housing units, 70.8% were owner-occupied and 29.2% were renter-occupied. The homeowner vacancy rate was 1.1% and the rental vacancy rate was 7.4%.
The largest townships/boroughs in Montgomery County include:
Montgomery County is a suburb of Philadelphia, the nation's sixth most populous city. Many Montco residents work in the city, but the county is also a major employment center with large business parks in Blue Bell, Lansdale, Fort Washington, Horsham, and King of Prussia attracting thousands of workers from all over the region. The strong job base and taxes generated by those jobs have resulted in Montgomery County receiving the highest credit rating of 'AAA' from Standard & Poor's, one of fewer than 30 counties in the United States with such a rating. In 2012, Moody's downgraded the general obligation rating to Aa1, and in 2018 the rating was revised back to Aaa.
Major employers include:
School districts:
Under Pennsylvania law, five types of incorporated municipalities are listed: cities, boroughs, townships, home rule municipalities (which can include communities that bear the name "Borough" or "Township") and, in at most two cases, towns. These boroughs, townships, and home rule municipalities are located in Montgomery County:
Census-designated places are geographical areas designated by the United States Census Bureau for the purposes of compiling demographic data. They are not actual jurisdictions under Pennsylvania law. Other unincorporated communities, such as villages, may be listed here, as well.
Even though the historic village of Valley Forge, as well as the park, are partially located within Montgomery County, the modern village is in Chester County, PA
The population ranking of the following table is based on the 2020 census of Montgomery County.
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The county is served by the SEPTA, which include bus, commuter rail, and interurban rail services. Pottstown Area Rapid Transit (PART) also provides bus services around the Pottstown area in the western portion of the county.
Commercial airline service is provided primarily by Philadelphia International Airport, one of the nation's largest commercial airports, located in Philadelphia and Delaware counties.
Other public use airports include Heritage Field in Limerick Township, Wings Field in Blue Bell, and Pottstown Municipal Airport in Pottstown.
The majority of the county has a hot-summer humid continental climate (Dfa). In most southern areas of the county and along the Schuylkill River including Pottstown a humid subtropical climate (Cfa) exists. The hardiness zone is 7a for the majority of the county and 7b in most areas south of Interstate 276. 6b only continues to exist in some very small higher areas in the north. https://planthardiness.ars.usda.gov/
As of May 19, 2025, there are 614,908 registered voters in Montgomery County.
Montgomery County historically was a stronghold for the Republican Party. The county was the only one carried by Barbara Hafer in the 1990 gubernatorial election over the incumbent governor, Bob Casey. However, the Democratic Party has made substantial gains in the county over the last quarter-century and gained the registration edge early in 2008.
Like neighboring Bucks County, the county voted Democratic during the Civil War era, voting Democratic between 1856 and 1876, except in 1860 and 1872. Like most of Philadelphia's suburbs, the brand of Republicanism practiced in Montgomery County for much of the 20th century was moderate. As the national parties have polarized, the county's voters have increasingly supported Democrats at the national level. The county voted for the Republican presidential nominee in all but three elections from 1880 to 1988, that being in 1892, 1912 and 1964. However, Montgomery County residents have voted for the Democratic presidential nominee since 1992, with the margins progressively increasing between every election, except in 2012. In the 2020 election, Joe Biden became the first Democrat to obtain over 60% of the county's vote.
Despite Donald Trump's victory in the state of Pennsylvania in the 2016 presidential election, Montgomery County was one of the few counties in Pennsylvania that swung in the Democratic presidential candidates' direction with Hillary Clinton winning Montgomery County with 58.87% of the vote, an improvement from Barack Obama's 56.6% vote share in 2012. In the 2016 U.S. Senate and Pennsylvania Attorney General elections, Montgomery County voted for Katie McGinty and Josh Shapiro, both Democrats.
Most county-level offices were held by Republicans until after the 2007 election, when Democrats picked up control of five row offices. Democrats have also won several elections in the Pennsylvania General Assembly in recent years, including two GOP-leaning State House districts in 2004, the 148th with Mike Gerber and the 153rd with current Governor Josh Shapiro. Today, although the county is very Democratic at the national level, at the state and local level, it is not specifically partisan.
In the 2004 United States Senate election, Republican Arlen Specter won the county over Montco resident Joe Hoeffel, but Democrat Bob Casey, Jr. out-polled Rick Santorum in the 2006 Senate election. In 2006, Democrat Rick Taylor unseated incumbent Republican Eugene McGill in the 151st, although Taylor lost in 2010 to Republican Todd Stephens and, in 2008, Democrat Matthew Bradford unseated incumbent Republican Jay Moyer in the 70th. Six of the county's 12 state house seats and four of the county's eight senate seats are now held by Democrats. All four statewide Democratic candidates carried Montgomery in 2008, with Barack Obama receiving 59% of the county's vote.
Montgomery County is governed by a three-person county commission. The current composition is two Democrats and one Republican. By law, the county commission must have one member of a minority party represented.
As of the November 2019 election:
On July 24, 2013, Montgomery County Register of Wills D. Bruce Hanes, a Democrat, announced he would begin issuing marriage licenses to same-sex couples, flouting Pennsylvania law banning such unions. Hanes called the commonwealth's ban "arbitrary and suspect", saying he believes it violates the Pennsylvania Constitution and the United States Constitution. The Republican administration of Governor Tom Corbett filed suit in the Commonwealth Court of Pennsylvania in an attempt to block Hanes from licensing same-sex marriage. Commonwealth Court Judge Dan Pellegrini ordered Hanes in September 2013 to stop issuing same-sex marriage licenses. After Federal Judge John Jones threw out Pennsylvania's ban on same-sex marriage in May 2014, calling it unconstitutional, offices in other counties were able to issue these licenses, while Hanes had to wait for the ruling against him to be removed.