John C. Frémont is one of our national heroes and pioneers. Besides conquering California, he is noted for his explorations, which he had been carrying on more than five years. His guide and friend was the famous trapper, Kit Carson, whose name is now borne by a prosperous city in Nevada. Once when Frémont crossed the Rocky Mountains, he carved his name on a boulder more than thirteen thousand feet above the sea, on Frémont Peak.
Frémont had also explored a vast tract of land in northern Mexico, which the United States wished to own. So, when the treaty of Guadalupe Hidalgo was signed, in 1848, it was agreed that Mexico should give up all claim to Texas as far south as the Rio Grande, and also to New Mexico and what was then called Upper California,—including all the land between the Gila River and the parallel of 42°,—in exchange for fifteen million dollars.
There was, however, soon after this some slight trouble about the boundary, so James Gadsden was sent to sign a new treaty. He bought for the United States another strip of land, south of the Gila River, for ten million dollars (1853). Because he did this, and signed the treaty, that strip of land is known as the “Gadsden Purchase.”