The archipelago has 2 groups. The North group is smaller and is named as "Rocas del Norte". There are 5 islands in this group, "Islote Cabezas", "Islote Peñailillo", "Isla Norte", "Islote Martínez" and "Islote Mendoza". In the South group are many islands, for example; "Islote Santander", "Islotes Vergara", "Isla Bartolomé" (the principal island), "Islote Pontevedra", "Islote García", "Isla Gonzalo" (the second longest) and "Islote Ester".