Abstract: A method for determining the location of a mobile station/cell phone making a call that may be an emergency 911 call. When the call is originated at the mobile station, the supporting wireless network receives data from a GPS device built into the mobile station as to the latitude and longitude of the device making the call. In addition, the mobile station transmits a barometric pressure measurement that allows the wireless support network to determine the altitude of the mobile station at the latitude and longitude reported by the mobile station. With that information in hand, the location of the mobile station making the emergency including its altitude relative to ground level at the mobile station's latitude and longitude can readily be determined.