Middle AmericaOnline version Physical Features of middle America by Yelena Talley 1 Sea of Cortes 2 Sierra Madre Oriental Mts. 3 Pacific Ocean 4 Gulf of Mexico 5 Yucatan Peninsula 6 Lake Nicaragua 7 Atlantic Ocean 8 Greater Antilles 9 Caribbean Sea 10 Isthmus of Panama 11 Lesser Antilles 12 Trinidad