This post was edited by Makena Layton on Jul, 2022
Here are some great sites for finding shape files:

http://www.cdc.gov/epiinfo/northamerica.htm

http://data.geocomm.com/ (General Files - country, states, etc.)

https://guides.library.unr.edu/c.php?g=185506&p=1225301 (AMAZING NEVADA DATA)

https://azconservation.org/science/?search&q=multi/category/gis/ (More on Arizona)