Franklin is rich in history and happens to be one of the most well-documented historic settlements in Northwestern Pennsylvania. Franklin exists mainly due to its strategic location at the confluence of French Creek and the Allegheny River. This location had long accommodated Indian settlements when, in the 1740's, Scottish fur trader John Fraser began a trading post. At that time, the entire Ohio Valley was the center of a conflict between the French and the English. A French expedition in 1749 laid claim to the site and, in 1753, the French expelled British traders and made plans to construct a fort around Fraser's abandoned trading post.
Later that year, a young George Washington, from Virginia, was dispatched to the region to warn the French that they were trespassing land claimed by England. The French defied the warning and built Fort Machault. Here, they amassed large forces of French, Indians, and boats in their plan to mount an attack on Fort Pitt, (in what is now Pittsburgh) in an effort to reclaim Fort Duquesne for France. This plan was thwarted, however, when the French had to scurry north to protect Fort Niagara and, before abandoning it, burned Fort Machault to the ground.
In 1760, seeing the strategic position of the site, the British were quick to erect Fort Venango to secure the territory for the Crown. However, this post survived only three years, as the entire garrison was massacred in a surprise attack by the Indians during Pontiac's Uprising in 1763. The American Colonial Forces then constructed Fort Franklin, named for patriot Benjamin Franklin, in 1787. Andrew Ellicott, who had surveyed for the site of Washington, D.C., was commissioned by the Commonwealth of Pennsylvania to lay out the town site of 1,000 acres that was to be designated "Franklin" in 1795. A final garrison was constructed in 1796 and remained until 1799, when it became the County's first jail. Four significant strongholds, all located within the present borders of Franklin, were constructed by three separate governments in the struggle to settle this rich area.
In the years following, Franklin continued a slow but steady growth, until the entire region became a center for worldwide oil production following Colonel Edwin Drake's drilling of the country's first commercially successful oil well in 1859 in nearby Titusville. Venango County oil production hit a peak in 1882. Unique to this valley, "Franklin's Heavy Crude" was sold at a premium price. In this frenzied period, Franklin offered the stability of an established community, even as wealth poured into it. This economic boom brought many changes to the face of Franklin. New commercial and residential structures were built as a result of this newfound wealth, employing several of the grand Victorian Era architectural styles of that time.
After the decline of the region's oil industry, Franklin settled into its role as the County Seat of Venango County and evolved into a stable manufacturing-based town. Manufacturing and light industry are still here today, but do not employ the large workforces that they once did.