America's public lands include some of the most scenic and highly valued resources in the country and thus attract nearby housing growth. NRS researcher Susan Stewart and cooperators at the University of Wisconsin and Oregon State University analyzed housing data from 1940 to 2030, within and surrounding each national park, national forest and wilderness area. They found that 28 million new housing units had been built within 50 km of protected areas and that 40,000 new houses were added within national forest boundaries. During the 1990s, housing growth averaged 13 percent nationally, but grew at 20 percent within 1 km of protected areas. If these long-term trends persist, another 17 million housing units will be built within 50 km of protected areas by 2030, greatly diminishing their conservation value. Concern about the integrity of protected areas has focused on developing nations, where resource use pressure taken off a protected area can intensify pressure on surrounding lands. In the U.S., our demands on resources are typically for scenic vistas and proximity to trails; this research alerts resource managers, state and local planning authorities, and conservationists that when houses are built to satisfy these amenity demands, forests are fragmented, habitat lost, migration corridors disrupted, and biodiversity reserves isolated.