Many miles of the the original Route 66 (US 66) are replaced by modern Interstate Highways - here in AZ the I-40. Anyhow, Arizona still has the longest stretch of the original US 66. This stretch starts west of Ash Fork and continues over Seligman, Peach Springs, Truxton, Valentine, Hackberry to Kingman, where it meets the I-40 again. This is the most popular part vor visitors but there's more. Shortly after Kingman the road becomes nowadays County Road 10 and proceeds over Oatman to Topock.
Flagstaff is a good starting point for your journey on the "Main Street of America' how the US 66 was nicknamed affectionately. The US 89 is the former US 66 and will already give a taste of the old time. Watch out for some Route 66 signs...
But the nicest part is yet to come. First head west on I-40 to Ash Fork which is approx. 50 mi west of Flagstaff. Then after ca. 6 further miles the Historic US 66 road starts at Exit 139. Your first stop then is Seligman, where the 'Route 66 romantic' begins. Store and gas station fronts look like if we're still in the middle of the 1900's - of course, this is made up for tourists but it's lovely done anyway. In Seligman you probbaly will take a lot of photos... Continuing on "Mother Road" you'll reach Peach Springs. Following has nothing to do with the US 66, but is definitely worth to mention. In Peach Springs you can turn shortly after the Hualapai Lodge right (north) onto the Diamond Creek Rd (BIA-6) and drive through the Hualapai Indian Reservation until reaching the Colorado River. Approx. 20 mi to drive.
But let's stick to the Route 66 stretch. You will pass and probably stop a couple more times when driving through Truxton, Valentine, Hackberry. Then in Kingman it's a must to take some time to visit the historic part of the town.
Most travelers now enter the I-40 in Kingman and continue their journey, but if you're here because of Route 66 you will follow the historic US 66 through Kingman to Oatman, Golden Shores and finally Topock where the Arizona stretch of the Mother Road finally hits the I-40 again.
Route Chicago - Los Angeles.
The connection between Chicago and Los Angeles exists since 1926. The road has a length of 2.448 mi. Purpose of the project was to connect the densely populated Northeast with Chicago as a major industrial hub with the thriving west.
It's still the shortest connection between both cities although the original stretches of the US 66 are not easy to locate (if they even still exist at all). Many stretches have been replaced by modern Interstate Highways. The original parts of Mother Road are most of the time marked with signs like 'Historic Route 66'.