The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly called the Interstate Highway System (or simply, the Interstate System), is a network of highways (also called freeways or expressways) in the United States that is named for the president who was in office and championed its creation. The Interstate Highway System is a separate system within the larger National Highway System. The entire system, as of 2004, had a total length of 46,837 miles (75,376 km).

While Interstate highways usually receive substantial federal funding and comply with federal standards, they are owned, built, and operated by the states or toll authorities. The original Woodrow Wilson Bridge, for example, part of Interstate 95 and Interstate 495, was maintained by the federal government; its new span is now jointly owned and maintained by the State of Maryland and the Commonwealth of Virginia.

The system serves nearly all major U.S. cities, with many Interstates passing through downtown areas. The distribution of virtually all goods and services involves Interstate highways at some point. Residents of American cities commonly use urban Interstates to travel to their places of work. The vast majority of long-distance travel, whether for vacation or business, uses the national road network; of these trips, about one-third (by the total number of miles driven in the country in 2003) utilize the Interstate system.