These are American Geographical Society "Know Your America Program" books published by Nelson Doubleday, dating from 1957 to the late 1960s — paperback booklets covering US cities, states and topics like railroads, illustrated with maps and black and white photographs.
There are 6 boxes with 6 books in each box except one box has 5 books and a map - Total of 35 books. Map is torn in some folding sections.