Hantaviruses are important human pathogens, occasionally emerging from animal reservoirs. However, both the biodiversity of hantaviruses in nature, as well as the frequency with which they have jumped species barriers in the past, are unclear. Here, we describe four novel hantaviruses (Huangpi virus, Lianghe virus, Longquan virus, and Yakeshi virus) that were sampled from bats and shrews in China. These viruses are different from known hantaviruses, with each representing a novel species. An evolutionary analysis of all known hantaviruses including the novel viruses described here reveals the existence of four distinct phylogenetic groups of viruses that infect a range of mammalian hosts, and which have sometimes exchanged genes through segment reassortment. Our analysis also suggests that hantaviruses might have first appeared in bats or insectivores, before spreading to rodents, even though rodents are currently the best documented hosts of hantaviruses. Because the phylogenetic trees of the hantaviruses do not always match those of their mammalian hosts, we conclude that both host-jumping and co-divergence have played important roles in hantavirus evolution. Overall, our study shows that bats are likely to be important natural reservoir hosts of hantaviruses from which novel hantaviruses may emerge in the future.