Yes, you can call 911 from a cell phone; however, the 911 operator will not immediately know your location as they would if you called from a landline phone. When calling from a cell phone, be prepared to give the 911 operator your address, city, and county.
If you are near the border of two counties or cities, the cell tower may connect you to the incorrect 911 communications center. If this happens, the telecommunicator will route you to the correct 911 center after confirming your address.
Federal Communications Commission (FCC) law requires wireless service providers to connect calls to 911, even if the caller does not subscribe to the provider's service. FCC law also requires wireless services to provide a caller's phone number and location to 911 communications centers. The location provided must be accurate within a range of 50 to 300 meters depending on available location technology.