Panama Pacific - International Exposition San Francisco - Columbia holding up the American flag

Front:
XA PANAMA 2AC 1915 INTERNATIONAL EXPOSITION SAN FRANCISCO CALIFORNIA 15-6

Back:
Post Grd 25- SPACE BELOW MAY BE USED FOR CORRESPONDENCE POSTAGE: UNITED STATES AND 1¢ POSSESSIONS CANADA MEXICO 2¢ FOREIGN ONLY THE ADDRESS MAY BE WRITTEN HERE PUBLISHED BY EXPOSITION PUB. CO., SAN FRANCISCO