The town of Hollidaysburg was first laid out in 1796; by 1814 it consisted of several houses and a tavern. Hollidaysburg became the main transfer point between the Pennsylvania Canal and the Portage Railroad, a gateway to western Pennsylvania. The canal and Portage Railroad spurred industrial and commercial development in Hollidaysburg in the 1830's. In 1836, Hollidaysburg was established as a borough.
When Blair County was organized in 1846, the Borough of Hollidaysburg was designated the county seat. This designation allowed the Borough to prosper when politicians and attorneys became attracted to the Borough.
In 1903, the Pennsylvania Railroad constructed a large switching yard and US Route 22 was directed through the Borough.