Understanding the processes that link global patterns of diversity to local ones remains a major challenge. Here, we use tools from biogeography, macroecology, and evolutionary biology to reveal how processes at evolutionary and ecological timescales have interacted to shape modern diversity patterns in North American mammals. Specifically, we used the geographic ranges of non-volant species to identify those species that show a >50% overlap with one of seven North American biomes. The subset of species with this strong association demonstrates a relationship of range area and body size indistinguishable from that of all North American mammals. For most biomes the pattern of range area and body size is significantly different than the continental pattern, suggesting that different mechanisms might generate diversity in each biome. We took a phylogenetic perspective to elucidate the effects of ecological sorting and evolutionary history on modern diversity, and found several distinct patterns. Many of the mammalian families with species showing biome preference exhibit a history of evolution in a particular biome with occasional contributions to other biomes. We integrate several approaches to address continental patterns of diversity and suggest that biomes play a critical role in the evolution of patterns of continental diversity.