Largo was one of the first places settled along the coast. 1n 1842, the Federal government passed the Armed Occupation Act which provided 160 acres of land for anyone who would live on the land for five years and agree to serve in the military, if needed. The McMullen and McKay families took the opportunity and settled in what was to become Largo. The McMullen’s settled around the north side of a large lake called Lake Tolulu; the three McKay brothers were each awarded 160 acres along a creek in the southwest area.

Since at least 1902, there was a "feed store" near the Atlantic Coastline railroad in Largo, that served the needs of local cattle ranchers, citrus and produce growers who were primary to the economy of the area. By 1910, Largo was an incorporated town with a population of 291. That was the year young John Gainey, operator of a nearby sawmill and concrete plant, built the present feed store building of rusticated block.