Before discussing the fascinating event of the first British fort to fall to American rebels in 1769 ~ essentially the beginning of the American Revolutionary War! ~ we should look at the situation of Fort Bedford at the time.
In the first place, Fort Bedford was not a British fort in 1769.
A contemporary document suggests when the British troops evacuated the fort. A petition by Garrett Pendergrass was sent to the Provincial Governor, John Penn in October of 1766. In that petition for recompense because his property had been confiscated by the Proprietors because Colonel Henry Bouquet wanted to build a fort on it, Mr. Pendergrass noted that "since the King's Troops evacuated that Fort, and the Avenues thereof, the Improvements of your Petitioner have been surveyed, under your Honor's Warrant afsd [aforesaid], for the use of the Honorable the Proprietaries." From that document, it may be assumed that the King's Troops, meaning the British, were no longer garrisoning the fort by October 1766. The fort would have been garrisoned thereafter by Cumberland (and later Bedford) County Militia for the safety of the local inhabitants up to and during the Revolutionary War.
The only source of the so-called 'capture' of Fort Bedford by American rebels is the autobiography of James Smith. The episode appears in "An Account of the Remarkable Occurrances in the Life and Travels of Col. James Smith". No record of the incident was recorded in the papers collected together in the Pennsylvania Archives. No record of the incident was recorded at the Cumberland County Court House. The only source of any information on the incident was written by James Smith himself, which he published in 1799, thirty years after the incident. He claimed to have executed his capture of the fort on 12 September 1769 ~ three years after the British troops abandoned the fort.
During the year 1769, the Amerindians had made a number of incursions into the region around the three-year-old town of Bedford. As noted by Smith: "yet, the traders continued carrying goods and warlike stores to them." Alarmed at the situation, a number of persons plundered the offending traders' stores, which they then destroyed. Although their actions were ostensibly for the safety of their fellow Euro~American settlers, the persons who plundered the traders; goods were arrested. Whether they were justified in attempting to deprive the Amerindians of ammunition was inconsequential in regard to the fact that ordinary citizens should not be allowed to take the law into their own hands. The arrested persons were fettered in iron shackles and confined in the guard-house in Fort Bedford.
The fact that the arrested persons were confined in the fort is not as significant as it might initially appear. Being held prisoner by red-coated British soldiers wielding bayonet-fixed muskets in a formidable stockade-surrounded fort is the stuff of a dramatic movie. But, as noted, the red-coated British troops had evacuated the fort three years earlier. And besides, activity at the fort, keeping watch for any attack by the Amerindians no doubt came to an end when Pontiac's War was quelled by Bouquet in 1765. That is probably why the British army evacuated the fort by the following year. Although James Smith did not state it in so many words in his memoirs, the persons arrested for plundering the traders' goods would have had to have been confined somewhere.
In 1769, the town of Bedford was not a county seat. The 'county' was two years away. There was no county gaol or prison at that time. There was, in fact, no borough in 1769; Bedford was simply a small frontier village. The rule of law in the region was enforced by the Cumberland County authorities, such as the sheriff and his deputies. So when James Smith made the statement in his memoirs that "some of these persons, with others, were apprehended and laid in irons in the guard-house in Fort Bedford . . .", the assumption should not be made that it was because the 'British army' was in control, or even present at the time, but rather because the fort, though in the process of decaying, would have been the most logical building, if not the only 'public' building, in which to confine the prisoners. The intention of the Cumberland County Sheriff and/or Constable was probably to transport the prisoners to Carlisle when it would become convenient.
Smith had engaged a friend by the name of William Thompson to gain information on where and how the prisoners were being held. When he and seventeen of the 'Black Boys' arrived near the village, Smith met up with Thompson, who informed him that "the commanding officer had . . . ordered thirty men upon guard." James Smith did not state that the fort was garrisoned by the British Army. By calling him the 'commanding officer,' the man heading the provincial authority could have been a sheriff or a provincial militia officer. Also, in regard to this point, the number of men 'ordered upon guard' did not necessarily mean that that number of men actually responded for the guard duty. By stating that the 'commanding officer' ordered thirty men to guard the prisoners, Smith implied that his little band of eighteen men going up against a superior force of thirty, would be more daring than it might actually have been.
At day-break, Thompson told Smith that the gate was finally opened and there were only three sentinels ~ the rest of the guard were 'taking a morning dram', suggesting that they were off getting drunk. Smith completed his narrative of the event with: "I then concluded to rush into the fort, and told Thompson to run before me to the arms, we ran with all our might, and as it was a misty morning, the centinels scarcely saw us until we were within the gate, and took possession of the arms. Just as we were entering, two of them discharged their guns, though I do not believe they aimed at us. We then raised a shout, which surprized the town, though some of them were well pleased with the news. We compelled a black-smith to take the irons off the prisoners, and then we left the place." How Smith knew that some of the townspeople were 'well pleased with the news' is not explained, and as no one felt compelled to record the event other than Smith himself, we will never know.
So while Smith and his Black Boys might have truly attacked the fort, it would have been Cumberland County Militia, rather than red-coated British troops, and only three who were in control of the fort at the time. Since Smith and his Black Boys left as quickly as they came, the fort itself was not really 'captured' by American rebels. Being captured would imply that it was taken possession of and held for a period of time. Smith and his men, according to his own words simply rushed in, stole some guns, freed the men who had legitimately committed a crime (and had been lawfully arrested) and ran off.
The incident didn't make much of an impression on anyone at the time. It wasn't even reported by any of the local justices of the peace or the sheriff to the Cumberland County Court.
Instead of flouting that "Fort Bedford was the first British fort to be attacked and captured by American rebels," it should more accurately be stated that Fort Bedford was the first already evacuated British fort with no British soldiers present to be attacked and immediately abandoned by a self-appointed vigilante group. But that doesn't sound very dramatic and noble, so James Smith sort of embellished the tale and laid claim to an honor he really didn't deserve. The lack of accuracy doesn't prevent re-enactors from staging mock attacks on the fort in present-day celebrations, though.