Actually, you raise a good point. For many years, both when I worked in government and when I simply phoned in the D.C. area and asked nicely, the CIA Map Library was very nice at giving copies of what they termed "base maps," at various scales. The maps on the CIA World Factbook are in this category -- perhaps with major cities shown, or with no cities/political boundaries at all, or perhaps nothing political, but terrain/language/resources. These were designed
to be drawn upon.
I would have thought that the full set was in the University of Texas collection, but it doesn't seem to be; I have no idea if the CIA main library (Office of Central Reference) still has a map division, or if that's moved to NGA. When the Pentagon was more accessible, there was a really great Army Map Library branch in the basement, with some self-service, but also very helpful librarians that would pull out CIA, DMA, National Geographic, oil company, and, probably if it was the right map, something issued by the Mogadishu Tourist Board.