This is a map of the I-5 highway that runs through all of California, Oregon, and Washington. This image is from www.i5highway.com and shows us just exactly where this highway leads. I find this interesting because this is the main highway people use to travel between Northern and Southern California. The interstate is nearly 1400 miles in length and connects many of the major cities that span California, Oregon, and Washington. You can just see how many cities that this highway runs through in Southern California. Portions of the highway were completed before the passage of the Federal Highway Act of 1956, but this act allowed funding for other parts of the highway that were finally completed in 1979.