Largo is the third largest city in Pinellas County, Florida, US, and is part of the Tampa Bay Area. Centrally located, it is the crossroads of the county. As of the 2010 census, the city had a population of 77,648, up from 69,371 at the 2000 census.Largo was first incorporated in 1905. In 1913, it became the first municipality in Pinellas County to adopt a council-manager government. It switched back and forth from "town" to "city" a few times, and became a city again in 1974.