In 2020, the freshwater mussels Louisiana Pigtoe Pleurobema riddellii (Lea, 1862) and Texas Heelsplitter Potamilus amphichaenus (Frierson, 1898) were categorized by the U.S. Fish and Wildlife Service as functionally extirpated/extirpated within the upper Sabine River basin of Texas and Louisiana with identified threats to population viability including changes in water quality. Purposes of this study were to update current knowledge (i.e., occurrences, relative abundances, catch per unit effort, and habitat associations) of Louisiana Pigtoe, Texas Heelsplitter, and other co-occurring mussel species within the Sabine River basin and to evaluate if water quality over a 50-year period could be a factor in the functionally extirpated/ extirpated categorization of Louisiana Pigtoe and Texas Heelsplitter within the basin. Surveys resulted in the collection of 28 freshwater mussel species and 9,244 individuals among 46 mesohabitats and five reaches of the Sabine River basin. Louisiana Pigtoe (n = 57) and Texas Heelsplitter (n = 7) were only observed in the upper Sabine. Louisiana Pigtoe was associated with swift current velocities, shallow depths, and gravel substrates. Texas Heelsplitter was associated with shallow, swift, riffle mesohabitats of sand and gravel substrates. Between 1960/1970s and 2020s, several water quality variables were generally within water quality standards and improved through time, indicating that water quality likely was not a limiting factor for freshwater mussels. Future monitoring is needed to further understand relationships between freshwater mussel communities and water quality.