Canadian (kənā´dēən), river, 906 mi (1,458 km) long, rising in NE New Mexico. and flowing E across N Texas and central Oklahoma into the Arkansas River in E Oklahoma. In the mid-1800s, the Canadian River valley was followed by pioneers going West along the Fort Smith–Santa Fe Trail. Eufaula Reservoir stores the water of the Canadian and North Canadian rivers; its dam generates electricity. Sanford Dam impounds Lake Meredith, which lies over one of the world's largest natural gas fields. The lake is part of Lake Meredith National Recreation Area (see National Parks and Monuments, table).