Mission 66 was a United States National Park Service ten-year program that was intended to dramatically expand Park Service visitor services by 1966, in time for the 50th anniversary of the establishment of the Park Service.

A national recreation area (NRA) is a protected area in the United States established by an Act of Congress to preserve enhanced recreational opportunities in places with significant natural and scenic resources. There are 40 NRAs, which emphasize a variety of activities for visitors, including hiking, camping, boating, fishing, swimming, biking, horseback riding, and wildlife viewing, in areas that include multiple-use management for both conservation and limited utilization of natural resources. They have diverse features and contexts, being established around reservoirs, in urban areas, and within forests. Due to their size, diversity of activities, and proximity to population centers, NRAs are among the most visited units of the National Park System, with six among the thirty most visited sites.