Settlers started moving west as soon as the land by the eastern rivers was claimed. Wanting the right to expand into more territory was one of the factors in the American Revolution, including anger at the Proclamation of 1763 that restricted further settlement. Indeed, many veterans of the Revolution received land grants in the west for their service. In the late 1700s to the early 1800s, the West could mean Ohio, Kentucky, Tennessee, and parts of Pennsylvania. As those places filled up, too, and immigrants kept on coming, they eventually spread across the plains and into the heartland.