Description: This is a detailed map of the city Callahan in Nassau County, Florida. Section Township Range (STR) is shown. This map shows state roads, US highways, railroads, tenant houses, businesses, air beacon, a church, a pool, camp, a cemetery, farm units and dwellings other than farms. Key to Florida Highway maps. Source: , Florida State Road Department (, FL: , 1940) Map Credit: Courtesy the private collection of Roy Winkelman.