Saxonburg is a borough in Butler County, Pennsylvania, United States. The population was 1,629 as of the 2000 census.
Saxonburg was founded in 1832 by John A. Roebling, who is known for the design of the Brooklyn Bridge in New York, and for innovation in producing wire rope. Roebling had set out with his brother Karl and a group of pioneers from Germany in 1831 to flee the general unrest and oppression in Europe. The two men, along with a handful of the people who accompanied them on the trans-Atlantic journey secured 1582 acres (6.4 km²) of land on October 28, 1831 from Mrs. Sarah Collins.
In November 1920 KDKA radio, regarded as the world's first commercial radio station, began broadcasting from East Pittsburgh, PA, but later located its transmitter in neighboring Clinton Township. The Roebling Museum in the borough maintains several artifacts.