BROOKS RANGE

northernmost extension of the Rocky Mountains in northern Alaska, U.S. It is separated from the Alaska Range (south) and the Mackenzie Mountains (southeast) by the lowlands of the Yukon and Porcupine river systems. It extends about 600 miles (1,000 km) in a westeast direction across Alaska, from the Chukchi Sea to the Yukon (Canadian) border, and reaches widths of 80 miles (128 km). Its peaks average 3,000 feet (900 m) in the west to 9,000 feet (2,700 m) in the centre and east; Mount Isto (9,058 feet ), near the Canadian border, is the highest point. The range is a watershed between the Yukon River drainage and that of the Arctic Ocean. Anaktuvuk Pass (2,200 feet ), near its centre, is the main means of access from the Yukon lowlands. The British and Richardson mountains, extending about 250 miles (400 km) southeast to the Peel River of Canada, are sometimes considered part of the range. Named for the geologist Alfred H. Brooks, the entire mountain group is within the Arctic Circle. Huge reserves of oil were discovered at Prudhoe Bay at its northern base, and the range is crossed at Atigun Pass by the trans-Alaskan pipeline en route to the Valdez terminal in southern Alaska.