Blair County is a county located in the U.S. state of Pennsylvania. As of the most recent data available, the county has a population of approximately 129,144 people, with a population density of about 245.52 persons per square mile.
The county spans a total land area of 526.00 square miles (1,362.00 square kilometers). The administrative center and county seat is Hollidaysburg, which often serves as a hub for local governance and services. The largest city within the county by population is Altoona.
Geographically, Blair County experiences varied elevations, with its highest point at Martinsburg 1,407 ft and its lowest point at Williamsburg 884 ft. The region operates in the UTC-5.