The meromictic character of Green Lake, Jamesville, New York, is described based on a biweekly monitoring program conducted for 14 months. A sharp chemical gradient was observed in the lower waters throughout the study, supporting the classification of the lake as meromictic. An isodensity plot is presented for the study period. Densities were estimated with an equation of state obtained from the literature, which incorporated depth, temperature, and specific conductance information. Temporal variations in total stability are depicted, which were mitigated by seasonal thermal stratification. The chemical stability component remained constant (closed system value of 32.4 g-cm cm−), and contributed only 5.7% to the total, for the maximum stability case. The work of wind in distributing the summer heat income (8,570 g-cal cm−) was 348 g-cm cm−. Based on the identity of the chemically enriched forms within the chemocline/monimolimnion, the low magnitude of the chemical stability, the large seasonal contribution of thermal stability to total stability, and the lake settling, it is probable that the lake is an example of biogenic meromixis.