If you are looking for faults in California use: How Close to a Fault Do You Live? (Bay Area Earthquake Alliance)
For faults in California and the rest of the United States (as well as the latest earthquakes) use the Latest Earthquakes Map:
- click on the "Basemaps and Overlays" icon in the upper right corner of the map.
- check the box for "U.S. Faults".
- mouse-over each fault to get a pop-up window with the name of the fault.
The Quaternary Fault and Fold Database has an interactive map for viewing faults within the United States and a fault database.
The Information by Region section of the Earthquake Hazards Program website has links to many resources for faults and earthquakes for each state in the United States.