Throughout the 20th century, the people of Thornbury sought stability in small-town life as this rural area continued a culture of neighbors helping neighbors. Residents built schools and churches, and Brinton Lake Colony and Tanguy Homesteads developed cooperative communities that made the area a strong place for communal life. The defining events of the century also touched Thornbury residents, including World War I, when a soldier wrote to his mother about living in a tent in the rain and hoping the Germans would continue to be kept on the move. In 1904, the Institute of Colored Youth, now Cheyney State University of Pennsylvania, moved to Thornbury Township from Philadelphia. Willcox Mills closed in 1926, the Wall Street crash in 1929 marked the start of the Great Depression, Philadelphia became home to the first computer in 1946, heavy snows collapsed the roof of the AME church in 1958 and the community gathered to rebuild, and Thornbury celebrated its Tricentennial in 1987.