Fort Augusta was a stronghold in Northumberland County, Pennsylvania, in the upper Susquehanna Valley from the time of the French and Indian War to the close of the American Revolution.

[3] The fort was positioned so as to prevent Native American war parties from descending the Susquehanna River, to serve as a refuge for civilians under attack, and as a staging area for military expeditions against enemy forces.

[6]: 59 [7] The plan of the fort had been previously drawn up by Governor Robert Hunter Morris, who wrote to Clapham on 12 June recommending "a square with one ravelin to protect the curtain where the gate is, with a ditch, covered way, and glacis.

"[6]: 54  In early July, Clapham marched with his troops from Fort Halifax, while eighteen canoes and bateaux carried supplies downriver, encountering numerous falls and rapids which hindered their progress.

[6]: 55 [8] On 14 August, Clapham wrote to Governor Morris: "We have the walls of the fort now above-half finished and our other works in such situation that we can make a very good defense against any body of French and Indians that shall seat themselves before us without cannon.

[14] Modifications and improvements continued to be made for months, and in late October, Clapham described the final stages of the fort's construction: "In eight or ten days more the ditch will be carried quite around the parapet, the barrier gates finished and erected, and the pickets of the glacis completed.

This army was gathered from the French posts at Duquesne, Kittanning, Venango and Le Boeuf and assembled at the mouth of Anderson Creek, near the present location of Curwensville, Clearfield County, Pennsylvania.

They dragged along with them two small brass cannon, but after reconnoitering found the distance too great for the guns to shoot from the hill opposite the fort, and the attack was abandoned.

"[18]: 424 [19] The fort at that time had a garrison of fewer than one hundred troops, and Colonel Samuel Hunter, the commander, made an urgent plea for reinforcements.

[22] During the mid-19th century, a wooden building stood over the underground chamber and at one time it was enlarged and strengthened to serve as the first jail in Northumberland County.