Separated from the main island of Japan by the Tsugaru Strait, and from Saghalien by the narrow strait of La Perouse, in shape an irregular triangle, extending from long. 139° 50' E. to long. 146° E., and from lat. 41° 30' N. to lat. 45° 30' N., its most northern point considerably south of the Land's End, Yezo has a climate of singular severity, a heavy snowfall, and, in its northern parts, a Siberian winter. Its area is 35,739 square miles, or considerably larger than that of Ireland, while its estimated population is only 123,000. The island is a mountain mass, with plains well grassed and watered. Impenetrable jungles and impassable swamps cover much of its area. It has several active volcanoes, and the quietude of some of its apparently extinct ones is not to be relied upon. Its forests and swamps are drained by innumerable short, rapid rivers, which are subject to violent freshets. In riding round the coast they are encountered every two or three miles, and often detain the traveller for days on their margins. The largest is the Ishkari, famous for salmon.<br><br>The coast has few safe harbours, and though exempt from typhoons, is swept by heavy gales and a continuous surf.