We provide new information from archaeological samples on the historical freshwater mussel fauna (Mollusca: Bivalvia: Unionoidea) of the Cuyahoga River (South Park site: occupied between ca. A.D. 950 and 1650) and Black River (White Fort site, occupation centered at ca. A.D. 1350), northeast Ohio. Data from these prehi storic sites are compared with information on extant mussel populations of the Cuyahoga River published between 1890 and 2000. The high representation at both archaeological sites of the species Actinonaias ligamentina, Elliptio dilatata, and Ptychobranchus fasciolaris suggests that these were· among the important clean water species in northeast Ohio prior to European settlement. By comparison, the modem mussel fauna of the lower Cuyahoga River (between Cleveland and Akron) contains none of these relatively abundant species, or any of the species represented in the archaeological material. The modern fauna of the lower river was established during the 20'" century. This fauna is a low diversity assemblage of pollution tolerant species represented by rare live individuals. The modem mussel fauna of the upper Cuyahoga River (between Akron and the source) suggests that the upper and lower reaches are effectively isolated from each other. Published records indicate little change in the fauna during the last three quarters of the 20'" century. Nevertheless, overall diversity, although substantially higher than that of the lower river, is considerably lower than that of the Grand River, which is located to the east of the Cuyahoga. Overall, the mussel fauna of the Cuyahoga River has changed greatly over time, most notably in terms of losses in diversity of clean water species and overall abundance.