a river in Kostroma and Ivanovo oblasts, RSFSR; left tributary of the Volga. Length, 152 km; basin area, 2,380 sq km. The Mera empties into the Gorky Reservoir opposite the city of Kineshma. It is fed by mixed sources, predominantly by snow. The mean flow rate 51 km from the mouth is 6.5 cu m per sec. The river freezes in November and thaws in April.