Interstate Commerce, in the United States, the traffic and trade that crosses state boundaries. Interstate commerce is distinguished from Intrastate commerce (wholly within one state) and foreign commerce (with other countries). “Commerce” involves the transportation of goods and passengers, the transmission of messages, and the agencies and facilities involved in transportation and communication, including railways, ships, trucks, buses, aircraft, pipelines, telephone and telegraph facilities, and radio and television stations.

The Constitution gives Congress power “to regulate commerce with foreign nations, and among the “states.” It prohibits Congress from imposing duties on goods exported from any state and provides that “no state shall, without the consent of the Congress, lay any imposts or duties on imports or exports.” These provisions arose out of the experience of the Confederation period (1781–87), when the states levied duties on imports from other states.

For nearly a century Congress made little effort to regulate interstate commerce. The most significant developments were in the courts. In 1824 the U.S. Supreme Court invalidated New York regulations affecting interstate commerce on the ground that Congress had exclusive power over such commerce. During the 1870's some states passed “Granger Laws” regulating railways and warehouses. The U.S. Supreme Court upheld these laws, but in 1886 it restricted state regulation to intrastate commerce. Only Congress had the power to regulate interstate commerce.

The first major Congressional legislation in this field was the Act to Regulate Commerce (1887), which established the Interstate Commerce Commission (ICC). The commission's authority was limited at first to railways. Its authority was gradually expanded to include all means of surface transportation.

The Federal Communications Commission (created by Congress in 1934) regulates interstate commerce in communication by telephone, telegraph, radio, and television. The Civil Aeronautics Board (1940) regulates civil aviation. The Federal Trade Commission (1915), Federal Energy Regulatory Commission (1977), and other independent agencies, as well as several federal departments, exercise certain controls over interstate commerce. By the mid-1980's, Congress had reduced the amount of regulation in trucking, railroad, bus, and airline transportation. In 1996 the ICC was abolished.