The old National Road was built in the early 1800s to connect the East to what then passed for the West, but which we know today as the Midwest. In the 20th century, the old road became US 40, more or less.
This is one of the “less” parts – the only gravel alignment of the National Road I’ve ever found, and I’ve explored it all, from Maryland to Illinois. This is County Road 725 South, near the tiny town of Reelsville in Putnam County, Indiana. US 40 lies about 1,000 feet to the south. For whatever reason, US 40 wasn’t routed along this alignment, and so it was never improved to modern standards. It’s about as close to the 1800s National Road experience as you can get.
I’ve written extensively about the National Road. Here’s a list of posts.