Several efforts was made to determine the source of the Mississippi River . In 1823 Italian explorer Giacomo Constantino Beltrami who had split from the Long expedition in Pembina , found Lake Julia which he believed was the source of the Mississippi River . The actual source was found in 1832 , when Henry Schoolcraft was guided by a group of Ojibwe headed by Ozaawindib ( " Yellow Head " ) to a lake in northern Minnesota . Schoolcraft named it Lake Itasca , combining the Latin words veritas ( " truth " ) and caput ( " head " ) .