United States of America as the worlds most developed country and a description of the country.US or United States of America (United States of America) is a country located in North America. It borders with Canada in the north and the south of Mexico. The population is a mixture according to the origin country, which derives from the Kingdom of the British but since its liberation from the reign of the countries immigrants come from many countries. Half of all population growth are just immigrants. The population is estimated at around 300 million. Approximately 3 / 4 the total population of the country are urban dwellers, the rest live in rural areas. The main city is the capital city in the country: Washington, in which 7 million people live, New York approximately 21.1 million people. These figures relate to the metropolitan, which includes the above-mentioned cities. The country is divided into states, which is 50 (this is reflected on the US flag on the state where each is represented as an asterisk). All states except Alaska and Alabama are divided into counties and the State from which comes the US or United Kingdom. These counties in 3048 as the time is not a number so large when taking into account the huge area on which the United States are America. The key document in the US is like in most countries of the then constitution. The Constitution was the first in the world and there are no major changes to the present day.