El Salvador is 4.2% larger than Massachusetts (USA).
Area: 21,041 km2 World Factbook
Population: 6,125,512 (July 2014) World Factbook
El Salvador, officially the Republic of El Salvador, is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador. Important cultural and commercial centers for Central America on the whole include Santa Ana and San Miguel. Wikipedia
Massachusetts, officially the Commonwealth of Massachusetts, is a state in the New England region of the northeastern United States. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. Wikipedia