Blossburg is a borough in Tioga County, Pennsylvania, United States. The population was 1,533 at the 2020 census. In 1792, a party of immigrants who were building the Williamson Road from Williamsport, in Lycoming County, to Painted Post in New York, under the leadership of Robert and Benjamin Patterson, discovered coal within the present town limits of …Blossburg is a borough in Tioga County, Pennsylvania, United States. The population was 1,533 at the 2020 census. In 1792, a party of immigrants who were building the Williamson Road from Williamsport, in Lycoming County, to Painted Post in New York, under the leadership of Robert and Benjamin Patterson, discovered coal within the present town limits of Blossburg. When the group reached the Tioga River, they established a supply camp at its banks.