Kilbirnie Loch (NS 330 543), is situated in the floodplain of between Kilbirnie, Glengarnock and Beith, and runs south-west to north-east for almost 2 km (1.2 mi), is about 0.5 km (0.31 mi) wide for the most part and has an area of roughly 3 km² (761 acres). It has a general depth of around 5.2 metres (17 feet) to a maximum of around 11 metres (36 feet). The loch is fed mainly by the Maich Water, which rises in the Kilbirnie Hills near Misty Law (507m or 1663 feet), and is drained by the Dibbs Water that runs into Castle Semple Loch, followed by the Black Cart, the White Cart at Renfrew and finally the River Clyde.