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Seventy-two caddisfly species in 36 genera and 15 families were collected along the Little Colorado, Verde, Gila, and Colorado rivers in Arizona. Brachycentrids, hydropsychids, limnephilids, and uenoids made LIP nearly 50% of the assemblage in forested sites above 2200 in. Hydropsychids, hydroptilids, and leptocerids made tip 75% of the assemblage in grassland watersheds between 2200 and 1000 in, and 80% at sites below 1000 in in desert watersheds. Species richness averaged 16 at sites above 2200 in elevation, 7 between 2200 and 1000 in, and 3 below 1000 In. H’ diversity was typically >3 at sites above 2200 in and <2.5 below 2200 in. Each river had distinct faunas likely due to isolation of drainages across semiarid landscapes. Low Sorensen similarity values were measured For caddisfly assemblages in the highly regulated Colorado River and the other 3 rivers. Only 17 species were collected at 14 sites along 700 kill of the Colorado River. Indicator caddisfly species are provided for altered and less disturbed drainages. We added 7 species not previously reported in Arizona for a total of 154 caddisfly species in the state. We provide a baseline of caddisfly indicators for monitoring changes in ecosystem health during the predicted long-term drought and population expansion in southwestern USA.