Cataloged maps, like books, have a call number. These maps are shelved numerically according to their call numbers in the map cases. Many maps appear on the Library's catalog. You search for a map as you would search for a book. The easiest method is to enter the geographic location (country, state, county, city, national park, region, river, etc.) i.e. "California" and the the term "maps". You will see a listing of all maps pertaining to California. However, you may want to limit your available resources. To do this you may enter a subject category with the geographical location., i.e. "California" "mines and mineral resources" "maps". 

Here is a short list of some of the most commonly used subject qualifiers: 

1. Administrative and political divisions 
2. Agriculture 
3. Botany 
4. Census districts 
5. City planning 
6. Earthquakes 
7. Ecology 
8. Faults 
9. Floods 
10. Forests and Forestry 
11. Geology 
12. Historical Geography 
13. Hydrology 
14. Land use 
15. Landowners 
16. Mines and mineral resources 
17. [place] maps, outline and base 
18. [place] maps, physical 
19. [place] Photo maps 
20. Real property 
21. [place] maps, tourist 
22. [place] maps, recreation 
23. Vegetation and climate 
24. Water resources development 
25. (Don't forget to always include the term "maps") 

• If you add a "1" to the last digit = subject.
• If you add a "2" to the last digit = physical area.
• If you add a "3" to the last digit = county.
• If you add a "4" to the last digit = city.
• Example:

G4360 = California

G4361 = California land use

G4362 = California Sacramento Valley

G4363 = California Butte County

G4364 = California Chico