Three centuries of shifting hydroclimatic regimes across the Mongolian Breadbasket

► We reconstruct streamflow in an agriculturally important region of Mongolia. ► We also analyze an earlier reconstruction to examine the full breadbasket region. ► The western breadbasket experiences a swinging pendulum of hydroclimatic regimes. ► Results suggest the eastern breadbasket has a steadier delivery of moisture. ► Water availability and demand mismatches can be acute across Mongolia's breadbasket.