a noble river in America, which waters about five-eighths of the United States, forming their western boundary, and separating them from the province of Louisiana and the Indian country. Its length has not been accurately ascertained, but it is conjectured to be upwards of 3000 miles. There are numerous tributary streams which fall into it from the W. and E.; and the country on both sides of the river, is said to be equal in goodness and fertility to any in North America. It is navigable as far as to what are denominated the falls of St Anthony, and some say farther. There are salt springs on each side of this river, which produce salt of an excellent quality, and large quantities of coal are found on its upper branches. Its mouths also form an island of considerable extent. These are situated between 29° and 30° N. Lat. and between 89° and 92° W. Long.