Most historians believe maize was domesticated in the
Tehuacan Valley of
 Recent research in the early 21st century has modified this view somewhat; scholars now indicate the adjacent
Balsas River Valley of south-central Mexico as the center of domestication.
Maya cultivated maize in numerous varieties throughout
Mesoamerica; they cooked, ground and processed it through
nixtamalization. It was believed that beginning about 2500 BC, the crop spread through much of the
 Research of the 21st century has established even earlier dates. The region developed a trade network based on surplus and varieties of maize crops.
An influential 2002 study by Matsuoka et al. has demonstrated that, rather than the multiple independent domestications model, all maize arose from a single domestication in southern Mexico about 9,000 years ago. The study also demonstrated that the oldest surviving maize types are those of the Mexican highlands. Later, maize spread from this region over the Americas along two major paths. This is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands.
Archaeologist Dolores Piperno has said:
A large corpus of data indicates that it [maize] was dispersed into lower Central America by 7600 BP [5600 BC] and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP [5000-4000 BC].
— Dolores Piperno, The Origins of Plant Cultivation and Domestication in the New World Tropics: Patterns, Process, and New Developments
Since then, even earlier dates have been published.
According to a genetic study by
Embrapa, corn cultivation was introduced in South America from Mexico, in two great waves: the first, more than 6000 years ago, spread through the
Andes. Evidence of cultivation in Peru has been found dating to about 6700 years ago.
 The second wave, about 2000 years ago, through the lowlands of South America.
Before domestication, maize plants grew only small, 25 millimetres (1 in) long corn cobs, and only one per plant. Many centuries of artificial selection by the indigenous people of the Americas resulted in the development of maize plants capable of growing several cobs per plant, which were usually several centimetres/inches long each.
Maize is the most widely grown grain
crop throughout the Americas, with 361 million
metric tons grown in the United States in 2014 (Production table). Approximately 40% of the crop—130 million tons—is used for corn
Genetically modified maize made up 85% of the maize planted in the United States in 2009.
After the arrival of Europeans in 1492, Spanish settlers consumed maize and explorers and traders
carried it back to Europe and introduced it to other countries. Spanish settlers far preferred wheat bread to maize,
cassava, or potatoes. Maize flour could not be substituted for wheat for communion bread, since in
Christian belief only wheat could undergo
transubstantiation and be transformed into the body of Christ.
 At another level, Spaniards worried that by eating indigenous foods, which they did not consider nutritious, they would weaken and risk turning into Indians. "In the view of Europeans, it was the food they ate, even more than the environment in which they lived, that gave Amerindians and Spaniards both their distinctive physical characteristics and their characteristic personalities."
 Despite these worries, Spaniards did consume maize. Archeological evidence from Florida sites indicate they cultivated it as well.
Maize spread to the rest of the world because of its ability to grow in diverse climates. It was cultivated in
Spain just a few decades after Columbus's voyages and then spread to
Italy, West Africa and elsewhere.
 Sugar-rich varieties called
sweet corn are usually grown for human consumption as kernels, while
field corn varieties are used for animal feed, various corn-based human food uses (including grinding into
masa, pressing into
corn oil, and fermentation and distillation into alcoholic beverages like
bourbon whiskey), and as chemical feedstocks.