Interstate 94 (abbreviated I-94) is the northernmost east-west interstate highway, connecting the Great Lakes and Intermountain regions of the United States. Its western terminus is in Billings, Montana at a junction with Interstate 90; its eastern terminus is the U.S. side of the Blue Water Bridge in Port Huron, Michigan, at the Sarnia, Ontario, Canada border, where together with Interstate 69 it meets Highway 402. I-94 is the longest interstate highway that does not end in a 0 or 5.

Interstate 94 is the only purely east-west interstate to form a direct connection into a foreign country (Canada). No such interstate currently ends at the U.S.-Mexico border, although I-905 in California was once designated as ending at the border. At Port Huron, I-94 crosses the Blue Water Bridge into Sarnia, Ontario and becomes Highway 402, which can be used by motorists going to Toronto. I-94's concurrency at that crossing, I-69, is posted east-west in eastern Michigan, but changes to north-south near Lansing and remains north-south in the remainder of Michigan and throughout its run in Indiana.

I-94 map