Fundulus kansae Garman (northern plains killifish; Fundulidae) was described in 1895 and “Kansas” was designated as the type locality. Based on the information available, a more specific locality is suggested: Big Creek near Ellis, Kansas. However, the continued presence of F. kansae in this region is uncertain. In several areas of western Kansas, including Big Creek, the distribution of F. kansae has been reduced since the late 1880s and its relative abundance has declined since the 1970s. These declines resulted primarily from habitat loss through dewatering of streams, although introduced predators, parasites, and fragmented streams also represent threats to the species. In other areas of western Kansas, especially in the upper Arkansas River basin, F. kansae has increased in relative abundance. However, these are probably short-term increases linked to declines in water quality, to which F. kansae is more tolerant than most other species of native fish. Thus, generally declining trends in distribution and relative abundance for Kansas populations of F. kansae suggest that the species is in need of conservation and warrants monitoring and additional study.