The county borders Philadelphia, the nation's sixth-largest city, to its southeast. In 2010, Montgomery County was the 66th-wealthiest county in the country by median household income. The county marks part of the Delaware Valley's northern border with the Lehigh Valley region of Pennsylvania. Montgomery County is included in the Philadelphia- Camden- Wilmington PA- NJ- DE- MD metropolitan statistical area, sometimes expansively known as the Delaware Valley. Montgomery County is geographically diverse, ranging from farms and open land in the extreme north of the county to densely populated suburban neighborhoods in the southern and central portions of the county. The county seat and largest city is Norristown. Montgomery County is located adjacent to and northwest of Philadelphia. As of the 2020 census, the population of the county was 856,553, representing a 7.1% increase from the 799,884 residents counted in the 2010 census.

It is the third-most populous county in Pennsylvania and the 73rd-most populous county in the United States. Montgomery County, colloquially referred to as Montco, is a county in the Commonwealth of Pennsylvania. Interactive map of Montgomery County, Pennsylvania

Haverford township adult school