Medulla is an unincorporated community and census-designated place in western Polk County, Florida, United States. It is part of the Lakeland–Winter Haven Metropolitan Statistical Area. Medulla is an affluent residential community located south of the Lakeland city limits, and north of the Mulberry city limits. Medulla neighbors Lakeland Highlan…Medulla is an unincorporated community and census-designated place in western Polk County, Florida, United States. It is part of the Lakeland–Winter Haven Metropolitan Statistical Area. Medulla is an affluent residential community located south of the Lakeland city limits, and north of the Mulberry city limits. Medulla neighbors Lakeland Highlands, and together the two communities make up much of what is known as south Lakeland. The population was 8,892 at the 2010 census. The area is addressed to Lakeland, with zip codes 33811 and 33813.