Catharine Township is located in eastern Blair County and borders Huntingdon County to the east. The Township encompasses an area of 30.8 square miles and was home to 724 people in 2010. The township is also home to Etna Furnance, the first iron furnace in Blair County. The site was built in the early 1800s and added to the National Register of Historic Places in 1973.
Much of the settled part of the township lies within the Canoe Valley. Several mountains surround the township’s border: its eastern border follows the crest of Tussey Mountain, part of its northern border follows the crest of Canoe Mountain, and its northwest border follows the crest of Brush Mountain.
The Frankstown Branch of the Juniata River forms Catharine’s southern border and part of its northern border. Fox Run, Roaring Run, and Yellow Spring Run are among the tributaries that feed into the Frankstown Branch. While the Frankstown Branch watershed occupies most of the township, Catharine’s western lands are part of the Canoe Creek watershed. Canoe Creek itself begins in the northwest corner of the township and flows south into Frankstown Township.