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.
Castlereagh River
In 1834, Andrew Brown explored the area near the Warrumbungles for his employer James Walker of Wallerawang, with the assistance of local Aboriginal people, and established several cattle runs, having already established "Cuigan" up from Mundooran at least in 1836. In 1837 Brown applied for simpoly an area in norther district of Bligh at Big River. In 1837 Robert Bennett applied for "Brumbel' or 'Briamble" on 'Big River' and in about 1839, he occupied "Kirban" station (adjoining Robert Lowe's 'Yalcogrin') which became the present-day Curban area. In 1836, ex-convict John Jude took up "Carlingangong" or "Carlingoing going" with John Hall, and then applied for 'Armatree' in 1839. There was a flurry of licence applications in 1836 when squatting was legalised and individual runs were set at a maximum of 16,000 acres with the requirement that licence fees be paid. This indicates that at least some of the applicants were already operating in the region: from the area of Mendooran down, Richard Rouse applied for "Mundooran", and for Breelong, Thomas Perrie for Eringanerin (then held in 1848 by John Meritt), and James Bennett at "Bearbong" as well as Curban, Robert Lowe already had Yalcogrin, and applied for Carlganda and James Lowe in 1839 for "Warree" further down past Armatree, where Andrew Brown had yet another run "Illamurgalia". Gibson and Patterson established 'Canamble' run for James Walker's ownership in 1840. Cox Brothers and WC Wentworth also took up licences.