Interstate 69 is a unique and evolving highway that spans multiple disconnected segments across the United States, with long-term plans to connect Michigan to Texas. Originally established as a north–south route from Indianapolis, Indiana, to the Canadian border at Port Huron, Michigan, I-69 has since been extended in piecemeal fashion, particularly in the southern states as part of the “Corridor 18” of the National High Priority Corridor system. The completed northern section travels through cities like Lansing and Flint before crossing the Blue Water Bridge into Canada, continuing as Highway 402 in Ontario.

In the southern U.S., I-69 is being built in stages through states like Mississippi, Tennessee, Arkansas, Louisiana, and Texas. Some of these segments use existing highways upgraded to Interstate standards, while others are entirely new alignments. Notable portions include the I-69E, I-69C, and I-69W spurs in southern Texas, which will eventually be unified as construction progresses. As of now, these segments serve major cities such as Memphis, Shreveport, and Houston, and aim to enhance trade and freight mobility throughout the central U.S.

Despite being incomplete as a continuous route, Interstate 69 is a critical infrastructure project with strong economic and strategic value. When finished, it will provide a streamlined north–south corridor stretching from the Great Lakes to the Gulf of Mexico and the Mexican border. The project has faced funding and environmental challenges, but progress continues, with various segments opening every few years.