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.

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.