United States Population 2015

According to the US Census Bureau's population clock, the estimated 2015 United States population (May 2015) is nearly 321 million. This differs a bit from the 325.1 million estimated by the United Nations.

By population, the United States of America is the third largest country in the world, a long way behind China (1.4 billion) and India (1.28 billion). It's most populous states are California (38.7 million) and Texas (26.8 million), and it's most populous city is New York City (8.2 million).

Largest state in the US

The largest state in the USA by population is California. The latest estimate recorded California's official population as 38.7 million.

If California was a country, it would be the 36th most populous in the world, slightly larger than Poland. It's economy would be the eighth largest economy in the world, with roughly the same GDP as Italy, a European country of 61 million people. Interestingly, though, although California is the largest state in the United States of America, it isn't the largest state in the continent of North America - that honour goes to Brazil's state of Sao Paulo.

Largest city in the US

The largest city in the USA is, of course, New York City. The city's population is estimated at an impressive 8.3 million, which makes New York City larger than the second and third most populous cities in the US (Los Angeles and Chicago) combined.

For much of the early 20th century, New York City was the largest city in the world. The stunning growth of cities elsewhere in the world means that today, New York is only the world's 19th largest city, sandwiched between Bangalore in India and Dongguan in China. It is, however, the world’s second largest city by GDP - it’s nominal GDP of $1.28 trillion puts it second only to the Japanese city of Tokyo.

US Census 2010

The United States census is held once every ten years, to count the number of people in the country and find out basic information about them - for example, age, sex and race. The last census was held in 2010, and the next census will be held in 2020.

The information collected in the census is used for many purposes. The first purpose is to ensure that each seat in Congress represents roughly the same amount of people. Take a look at this video to see how Congressional seats are apportioned:

National and State governments also use the information to plan services - for example, if they know that the population in an area is growing rapidly, they know that they will need to build more housing, schools and hospitals.

Every year, the Census Bureau releases annual population estimates. Statistical modelling methods are applied to the most recent census data to give an up to date picture of how the population of America changes between censuses.

You can read more about the census at the US Census Bureau website.

US Population History

Nobody is sure what the population of the Americas was before Columbus arrived in 1492, let alone the territory that is today the United States. Estimates vary wildly, but it seems to be accepted that the indigenous population of the Americas (the continents of North and South America combined) was between 50 million and 100 million in the 1490s. That includes approximately 15 million people living in the Aztec Empire and around 6 million Inca. The population of North America at the time is equally uncertain, and has been estimated at between 5 and 15 million.

Indigenous populations were hit hard by the arrival of European settlers. Firstly they were attacked by disease - some historians believe that over 50% of the population was killed by diseases including smallpox. And yet more were killed by wars, massacres and resettlement programmes. The Native American population of the United States reached a low point in the early 20th century, but has since been gradually increasing.

Formal census were not carried out during the colonial era, but records show that the colonial population grew from a shaky start of just 3,800 in 1610 to over 1 million in 1750. The population grew rapidly from then onwards and, when the first official census was held in 1790, shortly after independence, the population had grown to 3,929,214.

US Population Projections

The population of the US continues to grow, even today. The latest data from the Census Bureau shows that US population growth is running at 0.9% per year. They estimate that growth will continue fairly steadily over the next four decades, and that the US will reach a population of 400 million in 2039. If their predictions are correct, the US population in 2050 will be around 439 million.

The future US population will be different to the population today, though.

The country’s racial profile will be vastly different and, although whites will remain the single largest racial group in the the US, they will no longer be a majority. Growth in the Hispanic and Asian populations is predicted to almost triple over the next 40 years. The chart alongside this paragraph illustrates those changes.

The average US citizen of 2050 is likely to be older than the average citizen of today, and almost one in five people will be 65 or older. At the same time, the percentage of people who are working age (18-64) is likely to fall from 63% today to 57% in 2050. This will have huge implications for society as younger people work to fund the pensions and healthcare of the older.

Race and Ethnicity

In the census, people are asked to identify their race. The results from the 2010 census were as follows

  • White - 72.4%
  • Black or African American - 12.6%
  • American Indian or Alaska Native 0.9%
  • Asian - 4.8%
  • Native Hawaiian or Other Pacific Islander - 0.2%
  • Two or more races - 2.9%
  • Some other race - 6.2%

This doesn’t really tell the whole story, though, as it takes no account of those people who identify themselves as Hispanic. The census makes very clear that it does not consider Hispanic to be a race, but nonetheless it asks people whether they consider themselves to be of ‘Hispanic, Latino or Spanish origin’. In total, 16.7% of people identified themselves as Hispanic - just over 50 million people. People who identified as Hispanic mostly also identified themselves as White or Some Other Race, but this is not always the case.

As noted in the previous section, the racial and ethnic profile of the United States is changing, and it is likely that the relative proportions of each racial and ethnic group will change over the coming decades.


The census used to collect information about ancestry, but this question was removed from the 2010 census. The latest data, from 2000, shows that these were the largest ancestral groups in the US:

  • German - 15.2%
  • Irish - 10.8%
  • African American - 8.8%
  • English - 8.7%
  • American - 7.2%
  • Mexican - 6.5%
  • This map shows how the geographical spread of ancestral groups - those with German ancestry tending to dominate in the North and West of the country, those with Mexican ancestry more commonly found in the South West, etc.


    The language most commonly spoken in the US is English, which is the main language of 80% of American residents. Spanish is the main language of 12.3 residents and Chinese is the main language of 2.3%.

    Native American languages are the main language of 0.9% of residents. There is a wide variety of different Native American languages, many of which are on the endangered list. The most widely spoken is Southern Quechua, used by around 7 million people.

    Although legal documents are normally written in English, the US has no official lanaguage at the federal level. At the state level most, but not all US states have English as their official language. Hawaii is the only US state to have two official languages - English and Hawaiian.


    The United States Constitution enshrines the right to religious freedom and prevents the development of an official state religion. The lack of official involvement in religion means that no questions about religion are asked in the census and, as a result, limited and sometimes questionable data is available.

    The data on religion in this article and the associated chart is drawn from a 2007 study conducted by the Pew Forum.

    It reported that the vast majority of Americans are believers in a single religion - according to a 2007 survey, 78% of respondents identified themselves as Christians. Just over half (51.3%) of all Americans are Protestants, and almost a quarter (23.9%) are Catholic. Other Christian denominations make up 3.3% of the population.

    Jews (1.7%), Buddhists (0.7%) and Muslims (0.6%) are the next largest religious groups in the US and 16.1% of Americans declared themselves to have no religion.

    Life Expectancy

    The average life expectancy of a person born in the US in 2010 is 78.11 years. As in most countries in the world, US women have a higher life expectancy than men - women born in 2010 can expect to live for 80.69 years, while men can only expect to live for 75.65 years.

    Compared to the rest of the world, using data compiled by the United Nations between 2005 and 2010, the US is only 37th in the world - sandwiched between Cuba and Portugal. Interestingly, both the US Virgin Islands and Puerto Rico have higher life expectancies than those born on the continental US 79.4 and 78.7 years respectively). Hawaii is the US state with the highest life expectancy (81.5 years on average) and Mississippi is the US state with the lowest life expectancy (74.8 years on average).

    Within the US, there are variations in life expectancy between different races and also between people with different educational backgrounds. Although US life expectancy increased dramatically in the 20th century, it has declined slightly in the early years of the 21st century.

    US GDP / Economic Data

    Although the US has the largest overall economy in the world, it does not have the highest GDP per capita. With a GDP per capita of $48,328 the US ranks 11th in the world, way behind small countries like Luxembourg, with economies based around servicing international finance, but also behind some major countries including Canada and Australia. Average salary, calculated in 2011, is very similar at $45,230. The US state with the highest GDP per capita is Delaware ($69,667) and the state with the lowest GDP per capita is Mississippi ($32,967).

    United States Sex Ratio 2015

    49.235% Male
    50.765% Female

    Population Data via United Nations WPP

    United States Population Growth

    High levels of immigration combined with a healthy birth rate mean that, in contrast to many other developed countries, the US population continues to grow at a steady rate, increasing at around 0.9% each year.

    Data Sources
    1. World Population Prospects - Global demographic estimates and projections by the United Nations
    2. US Census Bureau - US Population Clock