The National Trust for Public Land's Center for City Park Excellence maintains the nation's most complete database of park facts for the 100 most populous U.S. cities. The total area covered by urban parkland in the United States exceeds one and a half million acres, with great parks ranging in size from the jewel-like 1.7-acre Post Office Square in Boston to the gargantuan 490,125-acre Chugach State Park in Anchorage. And their usage dwarfs that of the national parks—the most popular major parks, such as Lincoln Park in Chicago receive upwards of 20 million users each year, and New York's Central Park gets 37.5 million visits annually—more than seven times as many as to the Grand Canyon. Some cities have plenty of parkland that's well distributed around town; others have enough land but an inequitable distribution; others are short of even a basic amount of park space for their citizens.