Montgomery County, colloquially referred to as Montco, is a county in the Commonwealth of Pennsylvania. It is the third-most populous county in Pennsylvania and the 73rd-most populous county in the United States. 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. Montgomery County is located adjacent to and northwest of Philadelphia. The county seat and largest city is Norristown. 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.
