The Post Office Department issued its first postage stamps on...

  The Post Office Department issued its first postage stamps on...

"...On March 3, 1847, Congress authorized United States postage stamps. The first general issue postage stamps went on sale in New York City, July 1, 1847. One, priced at five cents, depicted Benjamin Franklin. The other, a ten-cent stamp, pictured George Washington. ..."

Reference: usps.com