The town of Hillsborough is the county seat of Orange County, North Carolina, United States and is located along the Eno River. The population was 6,087 in 2010, but it grew rapidly to 9,660 by 2020. Its name was unofficially shortened to "Hillsboro" during the 19th century. In the late 1960s, residents voted to change the name back to its original, historiā¦The town of Hillsborough is the county seat of Orange County, North Carolina, United States and is located along the Eno River. The population was 6,087 in 2010, but it grew rapidly to 9,660 by 2020. Its name was unofficially shortened to "Hillsboro" during the 19th century. In the late 1960s, residents voted to change the name back to its original, historic spelling.