There were brown people here, they were Aztec, and Inca, and the shambling remnants of the Maya (who were simply a tribe at that point without organization) on top of various other tribes along what is now the Yucatan and South America. They had advanced civilizations, grasped concepts of mathematics and science that Europe hadn't even fully understood, a fully developed system of medical treatment, including surgeries that were lightyears beyond what medical science and technique was elsewhere in the world at this time. Tenochtitlan was the one of the most advanced cities on earth.
They were quickly exterminated by war, infighting, the Spanish arrival and, over everything, being enslaved, overworked to death, and the virulent outbreak of Smallpox within their tribes which killed upwards of 85-90% of all native peoples. Whoever were left interbred with the Spanish colonists, creating the modern Yucatan people and the modern Mexican culture.
But our people were not here, in America, when white settlers from Europe began to arrive.