Freeport is the largest city in Stephenson County, Illinois, United States, and its county seat. The population was 23,973 at the 2020 census. Located along the Pecatonica River, Freeport is known for hosting the second Lincoln–Douglas debate of 1858, and as "Pretzel City, USA", due to a popular German bakery that became known for its prolific pretzel production in the 19th century. Freeport High School's mascot is the Pretzel to honor its heritage.