Far up the Darling, in latitude 30 degrees 5', Mitchell built a stockade and formed a depot, which he called Fort Bourke; near this spot the present town of Bourke is situated and now connected by rail with Sydney, the distance being about 560 miles.

Mitchell's second journey, when he visited Australia Felix, was made in 1835, and his last expedition into tropical Australia was in 1845.

On this expedition he discovered a large river running in a north-westerly direction, and as its channel was so large, and its general appearance so grand, he conjectured that it would prove to be the Victoria River of Captain Lort Stokes, and that it would run on in probably increasing size, or at least in undiminished magnificence, through the 1100 or 1200 miles of country that intervened between his own and Captain Stokes's position.

He therefore called it the Victoria River.

Gregory subsequently discovered that Mitchell's Victoria turned south, and was one and the same watercourse called Cooper's Creek by Sturt.