2003–2018 Created after the 2000 census, the 16th district was composed of a large portion of southern
Chester County, most of
Lancaster County, and a sliver of
Berks County, including the city of
Reading. The 16th stretched from the southwestern suburbs of Philadelphia in the east to the
Susquehanna River in the west, and north to include areas around Reading. In 2000, the 16th Congressional District was home to 646,328 residents, according to the U.S. census, and its population has increased since that year. Residents of Lancaster County made up the majority of the district's population, followed by Chester County and Berks County. The district was one of the Pennsylvania districts accused of being the result of
gerrymandering. Before 2018's redistricting, PA-03 was rated a Solid Republican seat by Cook. == Current counties and municipalities ==