Freshwater ecosystems are increasingly degraded by land use change, hydrologic alteration, and climate stress, yet their consequences for adjacent terrestrial food webs remain insufficiently quantified at large spatial scales. Aquatic insects, particularly mayflies, stoneflies, and caddisflies (EPT), provide a critical energetic and nutritional subsidy to riparian predators through adult emergence and are widely used as indicators of freshwater ecosystem integrity. Here, we test whether variation in EPT richness predicts riparian bird communities across continental scales. We integrated benthic macroinvertebrate monitoring data with over two million bird observations from eBird across 14,177 river sites in the contiguous United States. Using hierarchical hurdle models we show that EPT richness strongly predicts the prevalence of aerial insectivorous birds, with more than threefold higher prevalence at high- versus low-EPT sites. This association was consistent across hydrological, thermal, and geomorphological river types, including intermittent rivers, but was attenuated by urban land use and, to a lesser extent, intensive agriculture. Non-aerial insectivores and herbivores showed substantially weaker or inconsistent associations, supporting a trophic mechanism linked to emergent aquatic prey. Our findings provide continental-scale evidence that freshwater integrity sustains riparian bird assemblages through aquatic insect subsidies, highlighting that protecting rivers yields co-benefits that extend beyond the aquatic realm.