Visitors can check out Washington area national parks such as the Chesapeake and Ohio Canal, Ford’s Theatre and Great Falls National Park for free this weekend, and on several other dates in 2011.

The weekend is the first of many fee-free days established by the National Park Service at parks nationwide. National Park Week (April 15-17), the first day of summer (June 21), Public Lands Day (Sept. 24) and Veterans’ Day Weekend (Nov. 11-13) are also included.