After losing their farms and jobs during the Great Depression, many Americans in the 1930s traveled to states like Florida and California to look for work harvesting crops. To study this trend, the House formed the Select Committee to Investigate the Migration of Destitute Citizens in April 1940. Chaired by John Tolan of California, the select committee referred to this map as part of its investigation. In late 1941, the select committee sent staff members to Florida to better understand the agricultural labor supply problems and migration of laborers to the agricultural centers surrounding Lake Okeechobee in southern Florida. The map, created in 1935, was later hand-colored to reflect zones used to levy taxes on residents in those areas that would be used for drainage and reclamation projects in the Florida everglades.
With nutrient-rich soil and a favorable climate, the Florida everglades proved to be a prime environment for growing fruits and vegetables. By draining, or reclaiming, this area, the state increased its acreage of fertile farmland. The area around Lake Okeechobee became home to truck gardens, farms dedicated to growing and shipping—or trucking—out-of-season produce to northern markets. Migrant workers flocked to these successful farms during the Great Depression.