Our distances are not driving distances, but are calculated as a 'straight-line' (or point-to-point) distance from Portage Creek. A straight line distance ignores things like rivers, canyons, lakes, et cetera - it's truly a line drawn from Point A (ie- Portage Creek) to Point B.
Our distance measurements begin at a specific point in Portage Creek. The point that we are using is located at these GPS coordinates - Latitude: 58.9061, Longitude: -157.7175 [Map]. In this case, the coordinates for Portage Creek have been provided by the Geographic Names Information System (GNIS).