The Willamette Stone is the surveyor's monument that serves as the point of origin for all public land surveys in Oregon and Washington. It was established on June 4, 1851, by John B. Preston, Oregon's first Surveyor General, as increasing settlement and the passage of the Donation Land Claim Act made it urgently necessary in the Oregon Territory to extend the Public Land Survey System of 1785, which divided public lands into square-mile parcels of 640 acres. Appointed by President Millard Fillmore, Preston arrived in Oregon in April, 1851, explored the area, and selected this site so the primary north-south survey line, the Willamette Meridian, would pass west of Vancouver Lake and the primary east-west survey line, the Base Line, would not cross the Columbia River. Preston's original wooden stake was replaced in 1885 by the stone monument that became known as the Willamette Stone.