Also some of the best night sky in the country, and some areas are eerily still and quiet.
> In the stretch of highway between Fallon and Delta, Utah, a span of 409 miles (658 km), there are three small towns: Austin, Eureka, and Ely. This span is roughly the same distance as Boston, Massachusetts, to Baltimore, Maryland, or Paris, France, to Zürich, Switzerland.
Also known as the "Loneliest Road in America".
Eyre Highway runs east from Norseman in Western Australia for 1,200 kilometres (750 mi) across the Nullarbor Plain to Ceduna, South Australia.
It then crosses the top of the Eyre Peninsula as it continues eastwards for 470 kilometres (290 mi), before reaching Port Augusta.
The Kolyma Highway (aka Road of Bones) runs through over 2000 km of basically nothing, including the coldest place on Earth outside Antarctica.
https://en.wikipedia.org/wiki/R504_Kolyma_Highway
And they're building another 2300 km:
A) East of the Appalachian Mtns
B) Appalachians to Mississippi River
C) Mississippi to Rockies
D) Rockies to Pacific
Of those, (C) is one or two orders of magnitude more remote than the others.
On the east coast, it's hard to be more than 30 minutes from a Starbucks. In South Dakota, it's easy to be 2.5 hours from the nearest one.
Broadly speaking, you have the Northeast Corridor, which is more or less a continuous conurbation from DC to Boston.
Outside of that, the Eastern US generally follows European models of density, with clear densely-populated urban regions (Chicago being the largest city, but more minor cities like Indianapolis or Dayton correspond well to minor urban centers in European countries, population wise), in a field of rural areas where there's basically a quantum of civilization anywhere the land is flat enough to actually support it. There's kind of omnipresent human presence in the rural areas of, say, Ohio (not unlike rural Netherlands, say), while the mountainous regions like West Virginia sees strips of small towns nestled in every river valley while the ridgelines are largely empty (like a lot of the Alps).
The boundary between rural-but-populated and rural-but-unpopulated in the US is not so much the Mississippi River, but the 100°W longitude line, the High Plains (or roughly a line running from Oklahoma City through Wichita and Omaha up to Winnipeg along I-29 and I-35). From here, there's basically nothing until you hit the Front Range and the beginning of the mountains.
Once you hit the Front Range and you look west, you're in a kind of combination of the previous two zones. There's again large urban centers. In some of the big valleys--Columbia, Snake, Central, and Willamette--you see basically a small slice of European-style omnipresent human presence in rural areas. But outside of these areas, the area is largely thoroughly unpopulated, more so than even the High Plains, due to either being a desert, mountainous, or both.
It really is a feat of engineering when you think about it that highways were built and maintained over such vast distances and through some really inhospitable terrain. When driving that road I sometimes ponder what it was like building it.