Where breaks in the Dividing Range allow the intrusion of moist easterly air streams inland, annual median rainfall of 750 millimetres (30 in) or more is experienced further westward.

[28] The noted Wiradjuri warrior Windradyne came from the upper Macquarie River region, and was fatally wounded from a gun shot after a man hunt was commissioned by the crown in 1829.

[29] Near Carinda, between the Macquarie River and Marra Creek, the oldest evidence of bread making in the world (approximately 30,000 years old) was found at an ancient lake known as Cuddie Springs.

In 1813 Deputy Surveyor of Lands and explorer, George Evans wrote in his journal:[5] 30 November 1813: I have at length reached the Ridge I so much wished to do after walking about 2 Miles, where I had a prospect to the North for a great distance; A Mist arises from a part I suppose to be a River or a large Lagoon about 20 Miles Off; and on 9 December 1813: I have called the Main Stream "Macquarie River".Two years later Governor Macquarie inspected the country surrounding Bathurst and the Macquarie River and wrote on 10 June 1815, on his return to Government House in Sydney:[31] At the distance of seven miles from the bridge over the Campbell River, Bathurst Plains open to the view, presenting a rich tract of campaign country of 11 miles in length, bounded on both sides by gently rising and very beautiful hills, thinly wooded.

It is impossible to behold this grand scene without a feeling of admiration and surprise, whilst the silence and solitude, which reign in a space of such extent and beauty as seems designed by nature for the occupancy and comfort of man, create a degree of melancholy in the mind which may be more easily imagined than described.

From the fineness of the soil, the rain had made the ground very soft, rendering it difficult for the horses to travel..... Our day's journey lay generally over an open forest country, with rich flats on either side of the river ....

The vast body of water which this river must contain in times of flood is confined within exterior banks, and its inundations are thus deprived of mischief.....

The main bed of the river was much contracted, but very deep, the waters spreading to the depth of a foot or eighteen inches over the banks, but all running on the same point of bearing.

After going about twenty miles, we lost the land and trees: the channel of the river, which lay through reeds, and was from one to three feet deep, ran northerly.

This continued for three or four miles farther, when although there had been no previous change in the breadth, depth, and rapidity of the stream for several miles, and I was sanguine in my expectations of soon entering the long sought for Australian sea, it all at once eluded our farther pursuit by spreading on every point from north-west to north-east, among the ocean of reeds which surrounded us, still running with the same rapidity as before.

This astonishing change (for I cannot call it a termination of the river), of course left me no alternative but to endeavour to return to some spot, on which we could effect a landing before dark.... To assert positively that we were on the margin of the lake or sea into which this great body of water is discharged, might reasonably be deemed a conclusion which has nothing but conjecture for its basis; but if an opinion may be permitted to be hazarded from actual appearances, mine is decidedly in favour of our being in the immediate vicinity of an inland sea, or lake, most probably a shoal one, and gradually filling up by immense depositions from the higher lands, left by the waters which flow into it.

It is most singular, that the high-lands on this continent seem to be confined to the sea-coast, or not to extend to any great distance from it.By 1828, explorer Charles Sturt was commissioned to ascertain "the limits of the Colony" by following the Macquarie River "for the express purpose of ascertaining the nature and extent of that basin into which the Macquarie was supposed to fall, and whether any connection existed between it and the streams falling westerly".