The Yukon river is unique among rivers, in that it rises within I5 m. of tidal waters in the Dyea inlet on the Pacific coast, whence it flows in a north-westerly direction nearly 1,000 m., just crossing the Arctic Circle, where it turns south-west through the middle of Alaska, and then flows more than 1,200 m. until it reaches the ocean within sight of which it rose ; for we may properly call Bering sea a part of the Pacific ocean. This grand stream is also surprising in the length of navigation way it gives in proportion to its length, for less than 15 m. N. from where its tiniest stream lets trickle from the crest of Dyea pass lies Lake Bennet, whose head is the true beginning of steamboat navigation on this noble stream. From the starting-point of those same streamlets one can look down on other streamlets beginning their steep descent of the Dyea pass to the waters of the Lynn canal. The nearest harbour for ocean-going vessels is a poor one at St. Michael's island, about 6o m. north-east of the delta; here freight and passengers are transferred to flat-bottomed river steamers. These enter the delta and the river by the Aphoon pass, which is about 4 ft. deep at mean low water, the current varying from 1 4 to 4 m. an hour. The Lewes is navigable as far as White Horse rapids, which with Miles canon obstruct the river for a few miles. Above
them the stream is again navigable to its source, about 10o m. beyond. The White pass and Yukon railway from Skagway to White Horse (iii m.) overcomes these obstructions, however, for traffic and travel. The Stewart river, seldom less than 150 yd. wide, is navigable by light-draught steamers to Frazer falls, a dis tance of nearly 200 miles. The Tanana is navigable for about 225 m. to the mouth of the Chena, and above the mouth of the Chena it 'again becomes navigable for more than 25o m., including its principal upper tributary, the Nebesna. The Koyukuk, the second largest tributary, entering the Yukon about 600 m. up from its mouth, is navigable for 570 m. (Camden). Altogether the Yukon proper with its principal tributaries embraces more than 3,500 m. of navigable waters. The system is open to naviga tion from May until September.
H. Dall, Alaska and Its Resources (1870) ; F. Schwatka, Along Alaska's Great River (1898) ; Lieut. j. C. Cantwell, R.C.S., Report of the Operations of the U.S. Revenue Steamer Nunivak of the Yukon River Station, Alaska, 1899-19o1 (Washington) ; W. Ogilvie, Early Days on the Yukon (Ottawa) ; A. H. Brooks, "The Geography and Geology of Alaska," U.S. Geol. Survey, Doc. No. 201 (Washington, 1906).