The National Interstate Highway System is a network of highways in the United States designed for efficient transportation. Established in 1956, it connects major cities and regions, facilitating the movement of goods and people across the country. The system spans over 47,000 miles and is crucial for economic growth and national defense. Funded by federal and state governments, the Interstate System features high-speed roads with limited access, allowing for safer and faster travel. It includes numbered routes, with odd numbers running north-south and even numbers running east-west, making navigation easier for drivers.