Waldo is a city in Alachua County, Florida, United States. It is part of the Gainesville, Florida Metropolitan Statistical Area. As of 2020 census, …Waldo is a city in Alachua County, Florida, United States. It is part of the Gainesville, Florida Metropolitan Statistical Area. As of 2020 census, the population was 846, down from 1,015 at the 2010 census.