Pennsylvania forts in the French and Indian War

During the French and Indian War, the Province of Pennsylvania built a defensive chain of forts from the New Jersey border, southwest to the Maryland border, in response to numerous attacks on civilian settlements by Native American war parties under the direction of French officers and often with the aid of French troops. Settlers also built a number of stockaded blockhouses, as a second line of defense, in which they and their families could take shelter when attacked.

Source: Wikipedia — Pennsylvania forts in the French and Indian War (CC BY-SA 4.0)