In 1794, General “Mad” Anthony Wayne led a retaliatory battle occurred to avenge St. Clair’s defeat. The Indian Confederation, which included the Shawnee, was thoroughly defeated.
The Greenville Treaty was signed by tribal leaders the following year. The Greenville Treaty line passed thru the confines of modern Miami County and was intended to secure peace by ceding a large amount of land to American settlers while reserving the northwest portion of land for native tribes, including the Shawnee, Miami, and Wyandot. Shortly thereafter the treaty was signed, settlers began establishing farms throughout the area, including the area next to the treaty line (The treaty line is known today as Rangeline Rd).
In the spring of 1796 that Tecumseh and his followers moved from Deer Creek, south of Urbana to the banks of the Miami near Piqua. Then in autumn of the same year, they moved to the headwaters of the Whitewater River in present day Preble County. They maintained a village there until 1808, when Tecumseh and his brother, the Prophet, established Prophetstown in Tippecanoe County Indiana. In the next few years, Miami County settlers would continue to hear of Tecumseh.
General Anthony Wayne established two forts in Miami County. One fort was on the Stillwater River at Covington Ohio. It was known as Fort Rowdy. The other fort that Wayne established was known as Fort Piqua. Fort Piqua was at Upper Piqua, 400 yards northeast of the Johnston house. A detachment of soldiers remained stationed there from early 1794 to late 1795. After the treaty of Greenville was signed, the fort was soon abandoned. Prospective settlers became very interested in Upper Piqua.
After Wayne’s troops at Greenville disbanded, a man named Job Gard, who had been a army sutler (a civilian merchant licensed to sell to troops), came to the abandoned fort at Upper Piqua during the winter of 1796-97. Gard began dismantling the old fort in 1797. He picked out the best materials and floated them down river so he could build a cabin near what is now Harrison and Water Streets. The cabin stood on the edge of a hill just east of Harrison Street. He eventually sold out to John Manning and it is believed Gard moved east into present day Champaign County.
A "Factor" was a manager that were responsible for overseeing operations at a trading post, managing trade with Indigenous peoples, negotiating exchanges of furs for goods, and maintaining records of transaction. John Johnston began working as the U.S. Factor at Fort Wayne in 1802… just a year before Ohio became a state.
While working at Fort Wayne, Johnston approached Captain James Flinn concerning the possibility of purchasing of Upper Piqua. Captain Flinn claimed ownership of the land, but had never filed a deed. Flinn eventually defaulted on the taxes and Johnston purchased the land in 1804.
In 1809, John Johnston became the Federal Indian Agent at Fort Wayne. In 1810, he resigned from the position, giving a year’s notice. In 1811 he and his family moved from Fort Wayne to a log home at Upper Piqua.
The log home was located in the field across from the brick home that he began building at that time. The brick home was considered completed by May of 1812.
Sources for this information were: Rayner's First Century of Piqua, Ohio, The History of Miami County -1953, Archaeological and Historical Publications Volume XVI, Ohio Archaeological and Historical Quarterly Volume XXVII, and a 2025 Interview with Marla Fair ("Interpreter 1") at the Johnston Farm and Indian Agency.