Dele Ball was on the Big Piney, Wyoming, Bicentennial Committee. In 1975 she designed the Bicentennial cover envelopes for towns in Sublette County, Wyoming. Her papers contain eight Bicentennial cover envelopes she designed that were approved by the Big Piney Bicentennial Committee and one cover envelope approved by the La Barge Bicentennial Committee, with stamps that commemorate events significant in Wyoming history. The envelopes have typed histories inside written by Ball. She describes the background of the artwork on the front of the envelopes and the significance of the stamps.