When Clark was authorized by Virginia to raise soldiers for the Illinois campaign a letter to him written jointly by Thomas Jefferson, George Mason and George Wyeth intimated that "we have no doubt that some further rewards in lands in the country will be given to the volunteers who shall engage in this service in addition to the usual pay, if they are so fortunate as to succeed." They further intimated what they though this land gift ought to be, as to amount, and added: "For this we think you may safely confide in the justice and generosity of the Virginia Assembly."

This was not authoritative enough to be held out as an incentive to the soldiers and so probably cut little or no figure in the results, but Virginia did not forget the semi-promise. In 1781, nearly two years after the taking of Vincennes, the General Assembly adopted a resolution providing "that a quantity of land not exceeding one hundred and fifty thousand acres be allowed and granted to the … officers and soldiers … to be laid off in one tract … in such place on the northwest side of the Ohio [River] as the majority of the officers shall chose, and to be afterward divided among the said officers and soldiers in due proportion according to the laws of Virginia." In1783 another act was passed for locating and surveying the amount of land above specified, and a board of commissioners was appointed to take the business in hand. One thousand acres were to be laid out for a town site and the other one hundred forty-nine thousand to be surveyed for the individual claimants. The tract chosen was at and above the Falls of the Ohio and now lies mostly in Clark County, Indiana, though lapping over into Floyd and Scott Counties. It was first called the "Illinois Grant," the conquered territory being known as the "Illinois country," but later took the name of "Clark's Grant." The principal surveyor was William Clark, the cousin of George Rogers Clark. The thousand acres for the town site was located at the Falls of the Ohio, between the present Jeffersonville and New Albany, and was called Clarksville. The rest was apportioned among a total of 300 men, ranging in amount from 108 acres for each private to 8,049 acres to General Clark. There has been some criticism of this division, the feeling being that privates should have received 600 acres each, that being the amount suggested in the letter of Jefferson, Mason and Wyeth, above spoken of. Of the men who received lands in this tract by no means all settled there, but many sold their portions, preferring the cash benefit.

The surveys of Clark's Grant, taking the Ohio River for a base, do not correspond to the rectangular system as it exists over the State of Indiana Generally and thus the original donation can be readily located on any map that shows the congressional townships.

For exhaustive information on this subject see English's "Conquest of the Northwest."