The U.S. Highway System, formally known as the United States Numbered Highway System, is a network of roads and highways that span the country, established in 1926. It was the first major national road system, developed to facilitate transportation and commerce between states, cities, and regions. Prior to the development of the modern Interstate Highway System, U.S. Highways were the primary long-distance routes for motorists.

U.S. Highways are designated with numbered signs, with odd-numbered routes typically running north-south (such as U.S. Route 1, which runs from Maine to Florida) and even-numbered routes running east-west (like U.S. Route 66, which once stretched from Chicago to Los Angeles). Major highways usually have two digits, while shorter, regional routes are often assigned three-digit numbers, indicating they are spurs or connectors.

The system was designed to standardize the chaotic and inconsistent collection of state roads that existed before. It laid the foundation for the modern transportation infrastructure in the U.S., although many of its routes have been overtaken by the Interstate Highway System since the 1950s. Nonetheless, U.S. Highways remain vital for regional travel, rural areas, and connections between local and interstate routes.

Though not as heavily traveled today, the U.S. Highway System is still in use, offering access to scenic routes, smaller towns, and areas not served by Interstates, and it remains an iconic part of American road travel history.