Harrisburg's flag features a blue field with a yellow border and the municipal emblem centered. The emblem consists of a white keystone with a red border, incorporating the Capitol dome that denotes the city's importance as the capital of the Commonwealth of Pennsylvania.
The keystone is not a random symbol. Pennsylvania nicknames itself the "Keystone State." Geographically, Pennsylvania was at the center of the 13 original colonies. Historically, it played a pivotal role in the founding of the nation. The keystone on Harrisburg's flag proclaims this central status.
Mayor Edward Z. Gross proposed a design competition. The current flag was slightly updated in 1991 but maintains the original design.
Harrisburg is a small capital dominated by the state government. The Pennsylvania Capitol, completed in 1906, is a Beaux-Arts masterpiece with a dome inspired by St. Peter's in Rome. Teddy Roosevelt called it "the handsomest capitol building I ever saw." The flag captures this architectural and political pride.