Although Vandalia never was approved by the British Crown and did not have colonial government, some Anglo-American pioneers settled there. When the United States achieved independence in the American Revolutionary War, Vandalia-area settlers proposed (unsuccessfully) that Vandalia be admitted as a state called Westsylvania. They were opposed by the governments of Virginia and Pennsylvania, which both claimed the area.
In the 18th century, British land speculators attempted to colonize the Ohio Valley a number of times, most notably in 1748 when the British Crown granted a petition of the Ohio Company for 200,000 acres (800 km²) near the "Forks of the Ohio" (present-day Pittsburgh, Pennsylvania). The outbreak of the French and Indian War (1754–63) and Pontiac's Rebellion (1763–66) delayed colonization in the region.
After Pontiac's Rebellion, merchants who had lost goods in the war formed a group known as the "suffering traders", later known as the Indiana Company. At the Treaty of Fort Stanwix (1768), the British required the Iroquois to give a land grant to the "suffering traders" — most notably Samuel Wharton and William Trent. The land, known as the "Indiana Grant," was along the Ohio River and comprised part of the Iroquois hunting ground. When Wharton and Trent went to England in 1769 to have their grant confirmed, they combined forces with the Ohio Company to form a new consortium known as the Grand Ohio Company or the Walpole Company.
The Grand Ohio Company eventually received an even larger grant than the Indiana Grant. The development companies planned a new colony, initially called "Pittsylvania" (Wright 1988:212) but later known as Vandalia, in honor of Queen Charlotte (1744–1818), who was thought to be descended from the Vandals.
Opposition from rival interest groups and the outbreak of the American Revolutionary War (1775–83) prevented the development of Vandalia as a full colony. During the Revolutionary War, some settlers in the region petitioned the American Continental Congress to recognize a new province to be known as Westsylvania, which had approximately the same borders as the earlier Vandalia proposal. As both Virginia and Pennsylvania claimed the region, they blocked recognition of a new state.
- Cranmer, History of the Upper Ohio, 1:59–63
- Anderson, James Donald, "Vandalia: The First West Virginia?" West Virginia History, Volume 40, No. 4 (Summer 1979), pp. 375-92 online
- Cecil B. Currey, Road to Revolution: Benjamin Franklin in England, 1765-1775 (1968) pp 248-54
- Marshall, "Lord Hillsborough, Samuel Wharton, and the Ohio Grant, 1769- 1775" English Historical Review, (1965), 80:717-18
- Croghan to T. Wharton, December 9, 1773, "Letters of George Croghan," PMHB, XV (1891), 436-37. Any migration westward could help Croghan sell some of his own lands at Fort Pitt. James Donald Anderson, 1978
- Otis K. Rice and Stephen W. Brown. West Virginia: A History. 2nd Ed. University Press of Kentucky, 1994. p. 30. ISBN 978-0-8131-1854-3
- David W. Miller. The Taking of American Indian Lands in the Southeast: A History of Territorial Cessions and Forced Relocations, 1607-1840. McFarland, 2011. p. 41. ISBN 978-0-7864-6277-3
- Thomas J. Schaeper. Edward Bancroft: Scientist, Author, Spy. Yale University Press, 2011. p. 34. ISBN 978-0-300-11842-1
- Gipson, Lawrence Henry, The British Empire Before the American Revolution, 15 vols. New York: Alfred A. Knopf, 1946-1970, IX 457-88
- Carter, Clarence Edwin, Great Britain and the Illinois Country, 1763-1773, Port Washington, N.Y: Kennikat Press, 1970
- Abernethy, Thomas Perkins. Western Lands and the American Revolution. 1937/New York: Russell & Russell, 1959
- Alvord, Clarence W. The Mississippi Valley in British Politics, vol. 1. Cleveland, Ohio: Arthur Clark, 1917.
- Marshall, Peter. "Lord Hillsborough, Samuel Wharton, and the Ohio Grant, 1769- 1775", English Historical Review (1965) Vol. 80, No. 317 pp. 717-739 in JSTOR
- Steeley, James V., "Old Hanna's Town and the Westward Movement, 1768 - 1787: Vandalia the Proposed 14th American Colony", Westmoreland History, Spring 2009, pp. 20–26, published by Westmoreland County Historical Society
- Wright, Esmond, 'Franklin of Philadelphia' , Harvard University Press, 1988