Interstate 45 is an intrastate interstate highway located entirely within the state of Texas, United States. Like other "interstates", it is commonly referred to as I-45. Its odd number indicates that it is primarily a north-south highway. Its southern end is in Galveston, Texas at Texas State Highway 124 ; its northern end is in Dallas, Texas at Interstate 30. Unlike most of the other interstates ending in "5", it is not a border-to-border highway.

Length

Major Cities Along the Route

• Houston, Texas
• Dallas, Texas

Intersections with other Interstates

• Interstate 10 in Houston, Texas
• Interstate 20 in Dallas, Texas
• Interstate 30 in Dallas, Texas

Spur Routes

• Unmarked I-345 in Dallas, Texas. I-345 is less than one mile (1.6 km) long and connects the end of I-45 to the end of US 75 along the east side of downtown Dallas. It is signed northbound as US 75 and southbound as I-45.

Notes

• I-45 is not only an intrastate Interstate, but is also the shortest major Interstate (ending in 0 or 5). I-45 is also the longest intrastate Interstate to not touch any state or national borders (I-87 in New York is longer, but reaches the Canadian border).
• ISTEA states that Oklahoma can submit U.S. Highways 69 and 75, from the Texas state line to Interstate 40 at Checotah, Oklahoma, as an Interstate whenever it's ready for it. US 75 is controlled access from Dallas to the Oklahoma border, as is US 69 from McAlester to Muskogee. But the 125 mile (201 km) segment in between is built almost entirely at-grade.

Reference

• 2005 Rand McNally "The Road Atlas 2005" - newest feature- interstate mileage by state