Campo de Gibraltar is a comarca in the province of Cádiz, Spain, in the southwestern part of the autonomous community of Andalusia, the southernmost part of mainland Europe. It comprises the municipalities of Algeciras, La Línea de la Concepción, San Roque, Los Barrios, Castellar de la Frontera, Jimena de la Frontera, San Martín del Tesorillo and T…Campo de Gibraltar is a comarca in the province of Cádiz, Spain, in the southwestern part of the autonomous community of Andalusia, the southernmost part of mainland Europe. It comprises the municipalities of Algeciras, La Línea de la Concepción, San Roque, Los Barrios, Castellar de la Frontera, Jimena de la Frontera, San Martín del Tesorillo and Tarifa.