The recently-conducted 2010 Census showed a population of 112,336,538, making it the most populous Spanish-speaking country in the world.

Mexico is ethnically diverse, the various indigenous peoples and European immigrants are united under a single national identity. The core part of Mexican national identity is formed on the basis of a synthesis of European culture with Indigenous cultures in a process known as mestizaje, alluding to the mixed biological origins of the majority of Mexicans.

Mexican politicians and reformers such as José Vasconcelos and Manuel Gamio were instrumental in building a Mexican national identity on the concept of mestizaje. The term mestizo often used in literature about Mexican social identities carries a variety of meanings containing both socio-cultural, economic, racial and biological components and for this reason it has been deemed to imprecise to be used for ethnic classification, for which reason it has been abandoned in Mexican censuses.

In 2004, the Mexican government founded the National Institute of Genomic Medicine (INMEGEN) which launched the Mexican Genome Diversity Project. In May 2009, the Institute issued a report on a major genomic study of 300 mestizos in the Mexican population. Among the findings it was reported that over 80% of the population is mestizo and that the proportions of European and indigenous ancestry are approximately even.

A study presented by the American Society of Human Genetics has shown (based on genes) that, on average, Mestizo Mexicans are (genetically) 58.96% European, 35.05% “Asian” (Amerindian), and 05.03% African. Sonora shows the highest European contribution (70.63%) and Guerrero the lowest (51.98%) where we also observe the highest Asian contribution (37.17%). African contribution ranges from 2.8% in Sonora to 11.13% in Veracruz. 80% of the Mexican population was classed as mestizo (defined as “being racially mixed in some degree”).

The category of “indígena” (indigenous) can be defined narrowly according to linguistic criteria including only persons that speak one of Mexicos 62 indigenous languages or self-identify as having an indigenous cultural background. According with the National Commission for the Development of Indigenous Peoples as of 2005, there are 10.1 million Mexicans who speak an indigenous language and claim indigenous heritage, representing 9.8% of the total population.

The word “mestizo” is sometimes used with the meaning of a person with mixed Indigenous and European blood. This usage does not conform to the Mexican social reality where a person of pure indigenous genetic heritage would be considered Mestizo either by rejecting his indigenous culture or by not speaking an indigenous language, and a person with a very low percentage of indigenous genetic heritage would be considered fully indigenous either by speaking an indigenous language or by identifying with a particular indigenous cultural heritage.

Mexico represents the largest source of immigration to the United States. About 9% of the population born in Mexico is now living in the United States. 28.3 million Americans listed their ancestry as Mexican as of 2006. Per the 2000 U.S. Census, a plurality of 47.3% of Mexican Americans self identify as White, closely followed by Mexican Americans who self identify as “Some other race”, usually Mestizo (European/Indian) with 45.5%.

Mexico is home to the largest number of U.S. citizens abroad (estimated at one million as of 1999). The Argentine community is considered to be the second largest foreign community in the country (estimated somewhere between 30,000 and 150,000). Mexico also has a large Lebanese community, now numbering around 400,000.

In October 2008, Mexico agreed to deport Cubans using the country as an entry point to the US. Large numbers of Central American migrants who have crossed Guatemala’s western border into Mexico are deported every year. Small numbers of illegal immigrants come from Ecuador, Cuba, China, South Africa, and Pakistan.