I have caught them right below American Falls Dam, The river has some really nice ones in between American Falls and Walcott. I have not fished for smallies above American Falls. West of american Falls around Massacre Rocks is supposed to be good fishing too, I have not fished there yet, I hope to this year. There is supposed to be some bass in American Falls Reservoir too, hopefully someone from around Pocatello can answer. I live between Minidoka Dam (Lake Walcott) and Milner Dam.