Our distances are not driving distances, but are calculated as a 'straight-line' (or point-to-point) distance starting from Birches. A straight line distance ignores obstructions like rivers, canyons, lakes, et cetera - it's truly a line drawn from Point A (ie- Birches) to Point B.
Our distance measurements begin at a specific point in Birches. The point that we are using is located at these GPS coordinates - Latitude: 65.1350, Longitude: -153.5567 [Map]. In this case, the coordinates for Birches have been provided by the Geographic Names Information System (GNIS).