Clarion is a borough in Clarion County, Pennsylvania, about 100 miles (161 km) north-northeast of Pittsburgh and part of the Pittsburgh DMA. Clarion was settled in 1839 and incorporated in 1841. In the past, the surrounding area produced natural gas, oil, lumber and coal. Merely 2,004 people lived there in 1900, and only 2,864 lived there in 1910. The population was 6,185 at the 2000 census. It is the county seat of Clarion County, Home to the annual Autumn Leaf Festival and Clarion University of Pennsylvania.