CIA World Factbook: El Salvador - Features a map and brief descriptions of geography, economy, government, and people. - https://www.cia.gov/library/publications/the-world-factbook/geos/es.html
Lonely Planet: El Salvador - Includes facts and figures, culture, history, and tourist information. - http://www.lonelyplanet.com/worldguide/destinations/central-america/el-salvador/essential?a=culture
Peacecorps: El Salvador - Brief information of geography, economy, government, and culture. - http://www.peacecorps.gov/index.cfm?shell=learn.wherepc.LatinAmerica.elsalvador