In a four-month journey, Lt. Frederick Schwatka and his party rafted the Yukon from Lake Lindeman in Canada to Saint Michael near the river's mouth on the Bering Sea. In 1885, Lt. Henry T. Allen and four others left the Gulf of Alaska, followed the Copper River, crossed a mountain range, and traveled down the Tanana River to the Yukon, and portaged to the Kanuti and Koyukuk rivers. Allen went up the Koyukuk, then back down the Yukon, crossed over to Unalakeet on the coast, and then made his way to Saint Michael, exploring about 1,500 miles (2,400 km) of Interior Alaska.