Interstate means between or among states. In the United States, interstate highways are major roads that connect different states, letting you drive from California to New York or from Florida to Maine. These wide, fast roads were built starting in the 1950s to make travel and shipping easier across the whole country. You can recognize them by their distinctive red, white, and blue shield signs with numbers like I-95 or I-80.

Interstate commerce means business conducted between states, like when a company in Texas sells products to customers in Michigan. Interstate travel means journeying from one state to another.

Before the interstate highway system, cross-country trips took much longer on smaller, slower roads that wound through every town. President Eisenhower championed the interstate system after seeing Germany's efficient highway network during World War II. Today, interstates carry millions of travelers and transport goods that keep stores stocked nationwide. When your family takes a road trip and merges onto a big highway with multiple lanes in each direction, you're probably on an interstate highway.