Our distances are not driving distances, but are calculated as a 'straight-line' distance starting in Henderson. A straight line distance ignores things like rivers, canyons, lakes, et cetera - it's truly a line drawn from Point A (ie- Henderson) to Point B.
Our distance measurements begin at a specific point in Henderson. The point that we are using is located at these GPS coordinates - Latitude: 34.4851, Longitude: -86.8311 [Map]. In this case, the coordinates for Henderson have been provided by the Geographic Names Information System (GNIS).