An "Interstate" refers to a system of highways in the United States that connects multiple states. Officially known as the Dwight D. Eisenhower National System of Interstate and Defense Highways, it was established in 1956 to facilitate efficient transportation and improve national defense. These highways are designed for high-speed travel and typically have limited access points. Interstate highways are numbered, with odd numbers running north-south and even numbers running east-west. They are crucial for commerce, allowing goods to be transported quickly across long distances. The system also enhances connectivity between urban and rural areas, promoting economic growth and accessibility.