Crowds have become such a problem that many national parks charge admission and maintain long waiting lists for campgrounds and cabins. To add to the stress, development pressure on adjacent lands creates air and noise pollution, and maintenance funds are inadequate. Meanwhile, friction is intensifying between commercial interests eager to profit from the parks and environmental purists who would protect them from all human intrusions. Some parks supporters want to use federal budget surpluses to aid the parks, including purchasing fragile, new parklands. But critics say the nation can't afford any new parks, and that any budget surpluses should be used to protect Social Security.

Rachel S. Cox is a freelance writer in Washington, D.C., who writes about health, design and environmental issues for The Washington Post and other publications. She previously served as associate editor of Historic Preservation magazine. She holds a B.A. in English from Harvard University and studied architectural history at the University of California, Los Angeles. Her las report for CQ Researcher explored the "Home Schooling Debate."