From the confluence of the White Esk (rising near Ettrick Pen) and the Black Esk (rising near Jocks Shoulder, ) the Esk flows in a gradually south-easterly direction until it crosses the Border, whence it sweeps to the southwest through the extreme north-western territory of Cumberland and falls into the Solway. Of its total course of 42 mi (78 km), 12 mi (20 km) belong to the White Esk, 20 mi (32 km) are of the Esk proper on Scottish soil and 10 mi (16 km) are of the stream in its English course. On the right the Wauchope Water is the chief affluent, and on the left it receives the Meggat Water, Ewes Water, Tarras Water, Liddel Water and River Lyne — the last being an English tributary, and the previous forming the border between Roxburghshire and Cumberland.