The river of Seymarreh is an important major river in western Iran that affects regional and interregional interactions between Central Zagros and its surroundings. Discovering and locating Sassanian cities of Mäsbàzan and Mèhrjankàzàgh has been of great importance in Iranian archaeological studies during last hundred years. Following construction of the great Seymarreh dam and directing archaeological surveys during its building procedure, many ancient sites relating to Sassanian and other historical periods were recognized that just few of them excavated limitedly in rescue format. An area of about 45 Kilometers long and between nearly 100 to 3000 Meters wide became a massive man-made lake after operating the dam. This article focuses on rescue excavations held at two Sassanian sites of Sàrgàndäb and Sëràm-Šäh. Sàrgàndäb is a middle-size city with the area of nearly 4 hectares that a manor house build up with stone and plaster is found there; and Sëràm-Šäh includes remains of a fortress dominant throughout the entire Seymarreh valley. With the results of excavations in these two sites and some other Sassanian period ones, our point of view about cities` locations in the Sassanian state of Mèhrjan-kàzàgh should be reviewed and modified.
