The United States of America (USA), commonly referred to as the United States (U.S.), America or simply the States, is a federal republic country. The United States is the fourth-largest country by total area and third largest by population. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries. The geography and climate of the United States is also extremely diverse, and it is home to a wide variety of wildlife. The United States is a developed country and has the world's largest national economy, fueled by an abundance of natural resources and the world's highest worker productivity; world’s foremost economic and military power, a prominent political and cultural force, and a leader in scientific research and technological innovation and one of the world's largest manufacturers.

History - Paleo-Indians migrated from Asia to what is now the U.S. mainland around 15,000 years ago, with European colonization beginning in the 16th century. The United States emerged from 13 British colonies located along the Atlantic seaboard. Disputes between Great Britain and these colonies led to the American Revolution. On July 4, 1776, delegates from the 13 colonies unanimously issued the Declaration of Independence. The ensuing war ended in 1783 with the recognition of independence of the United States from the Kingdom of Great Britain, and was the first successful war of independence against a European colonial empire.

Driven by the doctrine of manifest destiny, the United States embarked on a vigorous expansion across North America throughout the 19th century. The United States emerged from World War II as a global superpower, the first country with nuclear weapons, and a permanent member of the United Nations Security Council. The end of the Cold War and the dissolution of the Soviet Union left the United States as the sole superpower.

Climate and Environment- The United States is the world's third or fourth largest nation by total area (land and water), ranking behind Russia and Canada and just above or below China.

The coastal plain of the Atlantic seaboard gives way further inland to deciduous forests and the rolling hills of the Piedmont. The Appalachian Mountains divide the eastern seaboard from the Great Lakes and the grasslands of the Midwest. The Mississippi–Missouri River, the world's fourth longest river system, runs mainly north–south through the heart of the country. The flat, fertile prairie of the Great Plains stretches to the west, interrupted by a highland region in the southeast.

The U.S. ecology is considered "mega diverse": about 17,000 species of vascular plants occur in the contiguous United States and Alaska, and over 1,800 species of flowering plants are found in Hawaii, few of which occur on the mainland. The United States is home to more than 400 mammal, 750 bird, and 500 reptile and amphibian species. About 91,000 insect species have been described.

Culture and Religion- Christianity is by far the most common religion practiced in the U.S., but other religions are followed, too. In a 2013 survey, 56% of Americans said that religion played a "very important role in their lives", a far higher figure than that of any other wealthy nation. English (American English) is the de facto national language, although there is no official language at the federal level.

The total reporting non-Christian religions in 2012 was 6%, up from 4% in 2007.Other religions include Judaism (1.7%), Buddhism (0.7%), Islam (0.6%), Hinduism (0.4%), and Unitarian Universalism (0.3%). The survey also reported that 19.6% of Americans described themselves as agnostic, atheist or simply having no religion, up from 8.2% in 1990.There are also Baha'i, Sikh, Jain, Shinto, Confucian, Taoist, Druid, Native American, Wiccan, humanist and deist communities.

The United States is home to many cultures and a wide variety of ethnic groups, traditions, and values. Aside from the relatively small Native American and Native Hawaiian populations, nearly all Americans or their ancestors settled or immigrated within the past five centuries. Mainstream American culture is a Western culture largely derived from the traditions of European immigrants with influences from many other sources, such as traditions brought by slaves from Africa. More recent immigration from Asia and especially Latin America has added to a cultural mix that has been described as both a homogenizing melting pot, and a heterogeneous salad bowl in which immigrants and their descendants retain distinctive cultural characteristics.

The US educational experience is the best globally. Many US colleges and universities are known worldwide for the quality of their academic programs.
A degree from a US college or university is a stamp of excellence that marks you for life. Even undergraduate students will find a solid network of support because the US is a “melting pot” of diverse cultures and there are more international students in the US than anywhere else. So you will get help not just from the foreign student advisor, but also from people in the local community

On the other hand, a US education is extremely expensive. Financial aid is very limited. You may be able to obtain similar training in your own country at a much lesser rate. You will have to balance the cost against the prestige and quality of a US education.

Do not count on being able to scrape up the funding after you arrive in the US. Getting a job is not an effective means of financing an education in the US. There are many restrictions on employment by foreign nationals, and some types of visas prohibit it totally.

Most international students are limited to on-campus employment. Even if you are able to find work, you will not be able to get a job that pays well enough to cover all your expenses. The typical on-campus job will pay no more than $1,000 to $2,000 during the school year and a similar amount during the summer vacation After you graduate, you might wish to work temporarily in the US. To do so, you will need to obtain H-1B status. Your degree must be in the area of expertise required for the position. You must have an offer of employment from a US employer. The employer must file paperwork to petition for H-1B status for you.