My good friend John Willinsky, bibliomeister and rock-a-blues maven, when I told him about my cross country plans suggested I pause when I crossed Highway 61. Always happy to take John's suggestions. But to my dismay I couldn't find Hwy 61, so could neither pause nor cross it. I saw no sign of 61 until I was in Natchez (MS), as I headed back west. Mystery solved when I did a little digging.
Hwy 61 (aka "Blues Highway") stretches from New Orleans to Wyoming, MN, generally paralleling the Mighty Mississip. (See map.)
What happens (see map below) is that 61 comes from the south and becomes 3rd St in Memphis (encircled, appropriately, in blue). Hegemonic I-55 (thank you Pres. Eisenhower, father of the interstate highway system and Cassandra of the military-industrial complex) comes from the SE, skips over 61 in South Memphis then heads north to intercept and appropriate it. 61 takes a sharp westward turn, rather than continuing north, and is effectively is erased at this point.
So... next trip I'm taking Hwy 61 from New Orleans to Wyoming (MN), and I'll know how not to lose it when I get to Memphis.