 U.S. Route 40 passes through the southwest corner of Addison Township, crossing over the Youghiogheny River Lake from Fayette County in the west, passing through the borough of Addison, and continuing south into Maryland.At the 2000 census there were 1,019 people, 435 households, and 301 families living in the township.The population density was 16.5 people per square mile (6.4/km²).