The population of Mexico and Central America is mainly Native American due to the region's long  indigenous history. These civilizations, like the Mayan and Aztec empires, were  established long before the arrival of European colonists in the 16th century.

 Although the Native American population was drastically reduced by European disease and colonization, a significant number of Native Americans survived and intermingled with  European settlers.  

 In contrast, the population of the United States and Canada consisted mainly of European settlers who arrived in the region in the 17th, 18th and 19th centuries. The indigenous peoples of these regions were also severely affected by European disease and colonization, and in many cases were forcibly removed from their land and resettled. This led to the displacement of many Native American communities and a significant decrease in their population. 

 In addition, large-scale immigration from Europe to the United States and Canada occurred in the 19th and early 20th centuries, which further increased the European population in those countries. 

In addition, policies such as the Indian Removal Act and Canada's residential school system  actively worked to assimilate indigenous peoples and suppress their cultures, further exacerbating the lack of Indian numbers in those countries.