Like topographic and soil maps, geologic and hydrologic maps provide useful information about the earth's composition and structure. Because they provide both descriptive and interpretive information about the landscape's physical properties, geologic and hydrologic maps are critical to a wide variety of applications, including property valuation, environmental consulting and clean-up, hazard prevention, exploration and development, civil engineering, city and regional planning (e.g., landfill siting, transportation planning, managing water and sewer systems), and locating natural resources.
Primary sources of geologic maps are state geological surveys and the U.S. Geological Survey, which has published thousands of maps and reports related to geology, hydrology, minerals, coal, oil & gas, and land use--dating back to the late 1800s.
| Series | Location | Call No. |
| Geologic Atlas of the United States | U.S. Gov't Info Atlas | I 19.5/1:[no.] |
| Water Resource Investigations | U.S. Gov't Info SuDoc | I 19.42/4:WRI-[no.] |
| Geologic Quadrangle Maps | U.S. Gov't Info Maps | I 19.88:GQ-[no.] |
| Hydrologic Investigations Atlases | U.S. Gov't Info Maps | I 19.89:HA-[no.] |
| Miscellaneous Geologic Investigations | U.S. Gov't Info Maps | I 19.91:I-[no.] |
| Scientific Investigations Maps | U.S. Gov't Info Maps | I 19.91/3:[no.] |
| Miscellaneous Field Studies | U.S. Gov't Info Maps | I 19.113:MF-[no.] |
| Bulletins | Engineering Library | QE75 .B9 |
| Professional Papers | Engineering Library | QE75 .P9 |
| Water-Supply Papers | Engineering Library | TC801 .U2 |
