With the discovery of gold in 1848, thousands of prospectors arrived in California. When it came time to create a state, the new residents wanted to make sure that California included all possible gold deposits in the Sierra Nevada mountain range, and thus drew its own borders. The American Revolution helped define the shapes of the original 13 colonies. The outlines of early states were often shaped by geographical boundaries, such as rivers.
These are the oldest historic cities in every state. The northern section of the western border of the Utah Territory, from which Nevada would be created, was first established shortly after California entered the Union in 1850 at 120 degree longitude. California could not extend eastward either because Mormon settlers were already looking to establish their own territory. Besides, no one from the Utah Territory had been invited to the convention, and maybe they wouldn't want to wake up one day and find out that they suddenly lived in California.
The diagonal line with California is described in the California constitution as a straight line from the intersection of 120 degrees longitude with 39 degrees latitude to the Colorado River at 35 degrees latitude. There was some feeling among Californians to establish the eastern boundary east of Salt Lake City, but others believed that the federal government would not allow a state of that size. The two largest contiguous states, California and Texas, determined their own borders because of their political power and concerns that they might separate from the United States. They took most of western Mexico in 1848, and the major cities of California wanted to ask Washington to become a state official, it was time to decide exactly what form the state would take.
The following timeline traces the territorial evolution of California, the thirty-first state admitted to the United States of America, including the process of removing indigenous peoples from their native lands or restricting them to reserves.