population density per sq km us
1 the U.S.A. ranks number 3 in the list of countries by population. 2  The population density in the United States is 35 per Km2 (92 people per mi2). 3  The total land area is 9,155,898 Km2 (3,535,111 sq. miles) 4  82.5 % of the population is urban (268,012,791 people in 2016)  The median age in the United States is 38.1 years.