On their return journey, they followed down the Maranoa, and at the old camp at St.George's Bridge, they were told by the natives that white men had visited the place during their long absence.

It was a singular and welcome feature of Mitchell's discoveries that they had always proved to be adjacent to civilisation, and to be suitable for immediate occupation.
The discovery of the Barcoo was the last feather in the cap of the Surveyor-General.

He was doomed to learn soon that it was not the river of his dreams, but only the head waters of that central stream discovered by Sturt, Cooper's Creek; but meanwhile the delusion must have been very gratifying.
In 1851 Mitchell was sent out to report on the Bathurst goldfields, and on a subsequent visit to England he took with him the first specimen of gold and the first diamond found in Australia.

He was for a short time one of the members for the Port Phillip electorate, but resigned, as he found faithful discharge of the duties to be incompatible with his office.

He patented the boomerang screw propeller, and was the author of many educational and other works, including a translation of the Lusiad of Camoens.