Jefferson Parish is celebrating America's 250th anniversary with a free, family-friendly event in downtown Gretna today. The day-long celebration begins at noon and includes USA Field Day, a classic car show, historic site activations, a patriotic parade, live performances by the Victory Belles and Bag of Donuts, and a drone show over the Mississippi River. Drivers heading to downtown Gretna should also expect traffic restrictions and road closures related to the celebration.