In 1818, John Oxley crossed and named Harrington and Farquhar inlets during a trip from the Hastings River, near Port Macquarie, to Port Stephens. The Manning River itself was first surveyed by Henry Dangar in 1825 and again in 1826 on behalf of the Australian Agricultural Company. Later in 1826, the river was named the Manning River by Robert Dawson for the Deputy Governor of the Australian Agricultural Company, William Manning. In the same year it was declared that the Manning was the northern limit of the Nineteen Counties, defining the areas of New South Wales where settlers were free to occupy.