What does interstate mean?
Interstate describes anything that connects, occurs between, or extends across different states of the United States. The adjective is especially common in political, commercial, and transport contexts, as in “interstate commerce,” “interstate cooperation,” and “interstate travel.” It can also be used as a noun for a major American highway crossing state lines, commonly abbreviated “I-,” as in Interstate 95. The term is chiefly American, and British speakers generally use “motorway” for the corresponding road. Compared with “national,” which can refer to a country as a whole, “interstate” points more specifically to relationships between individual states. Its familiar use in the Interstate Highway System has made it an everyday word for both long-distance road travel and activities that transcend state boundaries.
Existing, occurring, or conducted between different states of the United States.
"Negotiators reached an interstate agreement on transportation funding."
Common in political, economic, and transport contexts.
A major highway in the United States that crosses one or more state boundaries.
"Heavy snow caused closures on the interstate."
Chiefly American. As a formal highway name, it normally includes a number, such as Interstate 90.
Used mainly for separate interstate highways or routes as distinct entities.
"The proposed interstates would improve access to several growing cities."
Interstate means “between states”: even the name of America’s famous highway network is a compact lesson in geography.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does interstate come from?
The word combines the prefix inter-, meaning “between,” with state, the political division. The compound arose in an American political and commercial context during the early 19th century, when systems of transport and trade increasingly extended beyond individual states. It later became firmly associated with the nationwide highway network developed during the 20th century. Related forms include statewide, intrastate, and statesman.
How interstate is actually used
The adjective and noun are used chiefly in the United States. In British English, “interstate” is less common, and “motorway” is normally preferred for a major highway. As an adjective, it may take either “interstate” or “inter-state” in formal writing, although the closed form is standard.
Easily confused with interstate
Interstate activity connects or occurs between different states, whereas intrastate activity remains within a single state.
National refers to a country as a whole, while interstate more specifically refers to movement, commerce, or systems connecting individual states.