Back around 2004, I drove US-421 from its northern terminus in Michigan City, Indiana, to Fort Fisher, North Carolina.
There is no "Begin" sign in Michigan City. I drove it through town to the lake and didn't find any more 421 signs after I went north of US-20, where there is a 421 sign going south.
Went through Monticello, Indiana, home of famous Indiana Beach, which I saw for the first time. Then on to Indianapolis, where 421 now is aligned with the interstate bypass (I-465). I was sure it went through the city, probably on Michigan Road.
Southeast of town, US-421 is aligned with I-74 until near Greensburg, then on to Madison on the Ohio River, one of the most beautiful towns I've ever been on, especially with that park along the river where I had a picnic overlooking the striking US-421 bridge.
Then began one of the most striking drives I've ever been on to Richmond, Kentucky.
Coming Up. --RoadDog