From its beginning, the trail wound along Turnagain Arm, over Crow Pass, down the Eagle River Valley and northward to the trading post of Knik, Alaska, the largest town on the Upper Cook Inlet until the railroad town of Anchorage was founded in 1915. The trail then passed west through the valleys of the Susitna River and Yentna River and over the Alaska Range and Rainy Pass. West of the Alaska Range, the trail crossed the Kuskokwim River Valley to the hills west of McGrath and entered the Innoko River mining district and the town of Ophir. After Ophir, the trail went southwest through the Kuskokwim Mountains to Iditarod.