I just quoted what I learned in college… I copied the below clip from the Mn DNR web site, it accurately portrays the situation of introduction vs native…..
The smallmouth is native to the Mississippi watershed. It is abundant throughout the limestone stream of the Root and Zumbro drainages that are too warm to support trout. It is found in the boulder tributaries of the Mississippi in central Minnesota (such as the Kettle and Snake). The Mississippi itself holds large smallmouth bass as far north as Brainerd. Farther north, river smallmouth become increasingly scarce, though they occupy stretches of the St. Louis, Cloquet and Whiteface rivers.
The smallmouth also is native to many central Minnesota lakes, through it is far less common in this environment than the largemouth. The keys to their presence in these waters are clear water and suitable spawning gravel and rubble.
During the late 1800’s smallmouth were valued nearly as highly as trout and salmon and were transplanted to new watersheds with great fervor but little accurate record keeping. So biologist have been left to study historical records and postglacial drainage patterns to determine the presettlement range of the fish. Smallmouth bass probably are not native to the lakes that provide some of the best smallmouth fishing in the state, including Lake of the Woods, Rainy, Namakan, Vermillion and the large border lakes of the Boundary Waters Canoe Area Wilderness