The 25-cent Flag Over Yosemite coil stamp was issued on May 20, 1988, in Yosemite, California. The dedication ceremony occurred outside of the Yosemite Post Office, located at the famous Yosemite National Park.
The stamp features the US flag in the top half of the stamp, billowing above Half Dome, one of Yosemite's most striking examples of glacier-carved granite.
On February 14, 1989, the prephosphored version of the stamp was issued in Yosemite, California. A First Day of Issue ceremony did not occur, but the Postal Service offered first-day cancellations. In addition to enhancing a stamp's appearance, the use of prephosphored paper minimized revenue losses caused by reuse of stamps after removing the cancellation ink.
Designed by Peter Cocci, the stamp was engraved in the intaglio process by the Bureau of Engraving and Printing.
Postal Bulletin (April 21, 1988/ February 9, 1989).