Castlereagh River
The Castlereagh rises 20 km west of Coonabarabran in the heart of the Warrumbungle mountains at an elevation of about 850 metres. From its commencement upstream in the mountains the river initially flows east through the town of Coonabarabran. It then arcs round south and southwesterly to the village of Ulamambri, then south to Binnaway, and SSW to the small town of Mendooran which lies at the eastern side of the river's hook-shape. From here the Castlereagh flows in a westerly direction at the flattened bottom of the hook and then turns north-westerly towards the town of Gilgandra. From Gilgandra it continues to run northwesterly across the plains through Gulargambone and Coonamble, then continuing across expansive plains, with no urban centres, where elevations are less than 200m, until it joins the Macquarie River at its uppermost reaches beyond the Macquarie Marshes. Its confluence with the Macquarie is about 65 km SW of Walgett. Not far from the Castlereagh/Macquarie confluence the Macquarie itself joins the Barwon River at a place about halfway between Walgett and Brewarrina.
River Lagan
The River Lagan (; Ulster Scots: "Lagan Wattèr") is a major river in Northern Ireland which runs 53.5 miles (86 km) from the Slieve Croob mountain in County Down to Belfast where it enters Belfast Lough, an inlet of the Irish Sea. The River Lagan forms much of the border between County Antrim and County Down in the east of Ulster. It rises as a tiny, fast-moving stream near to the summit of Slieve Croob; Transmitter Road runs nearby. From here it continues on its journey to Belfast through Dromara, Donaghcloney and Dromore. On the lower slopes of the mountain, it is joined by another branch from Legananny (Cratlieve) Mountain, just opposite Slieve Croob. At Dromara, about four miles from its source, its height above the sea is 390 ft (119m). As the river continues on its journey to Belfast, it turns east to Magheralin into a broad plain between the plateaus of Antrim and Down.