Forks of the Ohio

The confluence of the Allegheny and Monongahela Rivers where the Ohio River begins. This geographic feature is the reason Pittsburgh existed: whoever controlled the confluence controlled the practical gateway to the Ohio Valley and the interior of the continent. The French recognized this in 1754 by building Fort Duquesne here; the British confirmed it in 1758 by immediately replacing it with Fort Pitt. The Continental Army maintained a presence here throughout the Revolution as the anchor of western frontier defense.