Greenwood Township was originally formed in 1767. It consists of two valleys, Pfoutz and Perry, the former being limestone soil and the most fertile section of the county lying east of the Juniata River, and the equal of the best lying west of it. Perry Valley was once known as Wildcat Valley, but an organization formed in 1884, known as the Farmers' Mutual Protection Association, was instrumental in having it changed to Perry Valley. The valley is ten miles long and four miles in width