US Land: The Lower 48

Factual Questions
1

What percent of the lower 48 is still unpopulated? A cite (preferably with a date to show its timeliness) would be appreciated, if possible.

2

I suggest that’s a pretty meaningless question. What does “unpopulated” mean?

I live in a suburb and there is some land on my lot that doesn’t have a house on it. Is that unpopulated land?

Across the street is a green space, an acre or so of common land with grass & a pond. Is that unpopulated land?

A few miles away is a farm with one house & 320 acres of corn. Is that unpopulated?

Behind the farm is another 320 forested acres that somebody owns and is natural except for a few trails through it, a fence around it, and asphalt roads on 3 sides. Is that uninhabited?

etc.

What you can meaningfully ask is “which counties have population densities below X people per square mile?” You might be able to ask something similar for squares of lat/long, or of range/township, or any other regularly-structured agreed-upon partitioning of the landmass.

3

As LSLGuy points out, the question is extremely ambiguous.

Some facts, though, could guide us towards a general understanding:

  1. About 3% of all the land in the United States is defined by the Census Bureau as “urban area,” comprising about four fifths of the population.

  2. “Rural residential area” is about 4% of the land area of the United States.

Cite for the above: http://www.ers.usda.gov/publications/EIB14/eib14g.pdf

About 40% of U.S. land area is used as farm, pasture, or managed woodlands.

4

Although the question is unanswerable without some criteria for “unpopulated”, there’s another aspect. Although the population ofthe US is increasing, there are parts of the US that used to be populated and now are no longer. In terms of area, the largest part of that would be abandoned farm land that is now returning to wilderness. But there is also urban land that is derelict, and no longer populated, even if ruined buildings remain: examples can be found everywhere from Detroit to New Orleans. Would the OP want to include this land, or is the word “still” important in the question?