The term "land use law" refers to the body of federal, state, and municipal legislation that exists to control the types of activities and structures that exist in different neighborhoods and areas of a region. In many communities, the primary type of land use law in effect are zoning ordinances that dictate whether commercial, industrial, residential, or other activities can occur within a city or county. Although the amount of land use legislation generated at the federal level has waned significantly in recent years, a number of major court cases have impacted land use law in the last several decades. Most notably, the National Historic Preservation Act of 1966 and the National Environmental Policy Act of 1969 have both proven to be watershed moments in shaping the course of land use law in the United States. The combined effect of these policies has been a dramatic diminishment in the amount of land that is available for new development, although many development decisions continue to be determined at the local level.