Designed by Irwin T. Catharine and built in 1936, this historic structure is a 2+1⁄2-story, L-shaped, brick building that sits on a raised basement. Created in the Colonial Revival style, it features a large brick and wood clock tower, gable roof, and rounded gables. Additions were built in 1966 and 1968.[2] The school was named for American merchant and politician Thomas Mifflin (1744–1800).