Minnesota, river, 332 mi (534 km) long, rising in Big Stone Lake at the W boundary of Minnesota and flowing SE to Mankato, then NE to the Mississippi S of Minneapolis. Earlier called the St. Peter or St. Pierre, it was an important route of explorers and fur traders. The river follows the valley of the prehistoric River Warren, the outlet of Lake Agassiz.
See E. Jones, The Minnesota: Forgotten River (1962).
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