Briar Creek is located in eastern Columbia County on the north side of the Susquehanna River. It is bordered to the east by Berwick, to the north by Briar Creek Township, to the west by South Centre Township, and to the south, across the Susquehanna, by Mifflin Township. Mifflinville is across the river southwest of Briar Creek, accessible by Market Street Bridge west of the borough limits.
Boroughs are the second most common form of municipal government in Pennsylvania; their number is exceeded only by the number of second-class townships. Pennsylvania’s 955 boroughs represent 37.2 percent of all general purpose municipal governments in Pennsylvania. The median number of boroughs per county is 11.
What outside Pennsylvania many would think are called “towns” are by law officially boroughs (often also spelled as boros) which are generally smaller than cities in terms of both geographic area and population. Most cities in Pennsylvania were once incorporated as a borough before becoming a city, and both began under the constitution as a township. Boroughs are not strictly classified by population and are administered through the borough legal code. Each borough elects a mayor and a council of three, five, seven, or nine members with broad powers, as determined by home rule measures. The borough offices of tax assessor, tax collector and auditor are elected independently. The borough council can also hire a borough manager to enforce ordinances and carry out the day-to-day business of the town’s administration and dictates of its council. The definition of boroughs is a town or district that is an administrative unit, in particular. Nineteen boroughs have also adopted home rule charters.