- United States. Bureau of Transportation Statistics49
- National Atlas of the United States32
- Geological Survey (U.S.)25
- Stackhouse, Cecil17
- Arndt, Raymond E.10
- Bawiec, Walter J.10
- Beikman, Helen M.10
- King, Philip B.10
- National Geophysical Data Center10
- Schruben, Paul G.10
- Geological Survey (U.S.) Minerals Information Team9
- United States. Bureau of the Census. Geography Division7
- Hunt, Raquel4
- Gap Analysis Program (U.S.)3
- Godt, Jonathan W.3
- United States. Federal Highway Administration3
- Waterborne Commerce Statistics Center (U.S.)3
- Institute for Water Resources (U.S.). Navigation Data Center2
- Rawson, Peg2
- Strocko, Ed2
