U.S. state flag consisting of a dark blue field (background) bearing a central coat of arms (arms, coat of) with black horses as supporters.

In 1777 a seal was created bearing the coat of arms now found on the state flag. The Pennsylvania legislature authorized the use of the coat of arms on a flag for the state militia on April 9, 1799, and variations on this flag design were used throughout the 19th century. Finally, on June 13, 1907, a state flag for nonmilitary purposes was approved by the legislature, and it is still in use.

Agriculture and commerce are represented in the coat of arms by the ship and the wheat sheaves (apparently copied from the municipal seal of Philadelphia), the plow (which appeared in the earlier coat of arms of Chester county), the wreath of corn and olive, and the horses in harness. The state motto, “Virtue, liberty and independence,” is inscribed on the ribbon below the arms. The standard of the Pennsylvania governor employs the same design on a background of white rather than blue.