Last august I found an area in a small river system that held a good number of really nice smallmouth, well above the average size that I normally catch. The river section that I was fishing is very swampy and just above a dam that holds back water and creates somewhat of a reservoir/lake. The bottom of the river here is very soft and my question is how far up stream would smallmouth migrate in search of better spawning grounds?

In rivers they will move a ways. I'd try to find the nearest hard bottom though.

The come out of my local lake and run as far up the creek as they can get 40 miles easy.

The come out of my local lake and run as far up the creek as they can get 40 miles easy.

awesome that's what I want too know

We caught some in a pond almost 45 miles away from the lake that they left(took the stream/river). We then fished the river/stream all the back to the lake and found them throughout. 

right on...the river starts in a lake that's about 15 miles up from the area we fished. The river looks fairly small up river a few miles from where we fish. Looks more like a stream on google earth. The lake from what I hear has lots of rocky coves and shoreline so we are planning to fish the lake as soon as the ice melts and water temps warm. So its very possible that the big bass we we get down river could be up river in the lake for the pre spawn.

Good Luck.......smallmouth are know to carry suitcases.