The route from Tok in Alaska to Dawson City in Yukon covers about 300 km but can take 7 to 8 hours because two thirds of the Top of the World Highway is gravel. The road closes in late September, and some motorhome rental companies prohibit driving on it. A free ferry across the Yukon River, funded by the Yukon government, operates 24 hours a day. The northern lights were observed from Midnight Dome outside Dawson City.