- California is bordered by Oregon to the north, Arizona to the southeast, and Nevada to the northeast and east.
- The country also shares an international border with Baja California of Mexico to the south.
- Before California’s modern-day boundaries were established, the area was claimed by various parties with borders often created in the sand by Mexicans, Indians, Spaniards, and Americans.
Located in the Pacific Region of the United States (US), California is the country's most populous state. It houses 39.5 million residents across an area of about 423,970 sq. km (163,696 sq. miles). California joined the Union as the 31st member on September 9, 1850.
California is bordered by Oregon to the north, Arizona to the southeast, and Nevada to the northeast and east. The country also shares an international border with Baja California of Mexico to the south. The state has a coastline on the Pacific Ocean to the west.
Exploring California's Borders
The Border Between Arizona and California
The Colorado River sets the boundary between the two states. However, the boundary between the two states had been subject to disagreements between the states of California, Nevada, and Arizona due to the periodic change in the river's course as a result of meandering. In the 1920’s the friction between the states was particularly intense due to jurisdictional issues, taxation, farm allotment, and issuance of property titles. The dispute led to the formation of the Colorado River Boundary commission in 1923 to settle the matter. The commission was renewed years later to shed clarity on matters to do with the border. The commission completed its duties in 1967, and its authority was later repealed in 1991.
The Border Separating Nevada and California
The boundary between the state of California and Nevada was described in 1849 by men who had little knowledge on the subject. The resulting boundary led to years of confusion and disagreement. Following the Mexican-American War and the Guadalupe Hidalgo Treaty in 1848, the present day California struck gold the following year in the American river thereby raising its profile. The discovery of gold in the area led to phenomenal growth and set the path for California's journey to join the Union as a state. The description of California's borders began at a constitutional convention held in 1849 that brought together American settlers, Californios, and miners together at the Colton Hall, Monterey, a former Mexican Capital.
Some members of the convention proposed that California includes the whole of Upper Mexico as it was known by the Mexicans. The proposal meant that the Great Basin and parts of Arizona and Utah would become part of California. Others advocated for a much more modest proposal with the borderline running along the Sierra Nevada Mountains which they argued made more political and geographical sense. It was also noted that governing a region as large as Upper California would be virtually impossible. The Mormons who lived near the Salt Lake were not included in the convention and it was thought that they would oppose being involuntarily drawn into a new state. The delegates eventually settled on the more modest proposal that drew the boundary along the Sierra Nevada Mountains. James M. Jones proposal was adopted. The state of California was hastily welcomed into the Union in September 1850 without proper territorial borders partly due to the massive wealth in the state. That left many people on the poorly defined boundary such as those on the 120th meridian not knowing whether they lived in Utah or California.
Determining the Exact Borderline with Nevada
Some of the challenges that were encountered while determining the borders to the east of the state were locating the geographical coordinates on the ground. The challenge was borne as a result of the use on longitudes and latitudes in the description of borders which seemed quite straight forward on paper. Determining where the imaginary lines fell on the ground proved much more difficult. Efforts to establish the exact borderlines with the state of Nevada lead to years of disagreements. The 1873 Von Schmidt border line north of Lake Tahoe had been accepted by both states but had not been adopted by the legislature of both states. The Houghton-Ives line was considered the borderline from Lake Tahoe to Oregon, the actual line on the ground was however yet to be determined. In 1977, the State of California brought a lawsuit against the state of Nevada in the United States Supreme Court in a bid to determine the actual boundary and prevent confusion on jurisdiction and tax collection. The Supreme Court finally determined the boundary between the two states in 1980. The court decreed that the boundary would be comprised of the Von Schmidt line between Oregon and the northern shore of Lake Tahoe as well as the USC&GS Pioneer that originated from the south of Lake Tahoe and run to Colorado River.
The Border Separating the State of Baja, Mexico, and California
Before California’s modern-day boundaries were established, the area was claimed by various parties with borders often created in the sand by Mexicans, Indians, Spaniards, and Americans. Due to claims by the various groups, the creation of the borders inevitably turned political. California’s southern border led to the separation of two cities namely San Diego and Tijuana which formerly shared the same ecosystem and country. The border formerly demarcated San Deigo as part of the American State of California. The establishment of the border with the Mexican State of Baja was determined by the Mexican-American war and the consequent Treaty of Guadalupe Hidalgo which was signed in February 1848. The Mexican-American war was as a result of a border dispute with the Mexicans claiming the Nueces River as its northern border while the US held the actual border was the Rio Grande further to the south. The war was declared in 1846 after Mexican soldiers attacked American troops who had moved south of the Nueces. The US emerged victors and took up large parts of northern Mexico which are occupied by the modern-day states of New Mexico, Utah, Colorado, Arizona, and California. Despite the treaty ending hostilities between the two nations and establishing a new border on paper, actual demarcation of the border on the ground proved to be more challenging than expected. A joint effort by the two nations was made to demarcate the border with William Hemsley Emory leading the American team and Jose Salazar leading the Mexican Team. The teams met in July 1848 at a point to the south of the Port of San Diego as the starting point of the boundary.
Current Status of California's Border Disputes
Border disputes with neighbors have been largely resolved. Currently, California is now home to up to 39.6 million people and holds the record as the most populous state in the country. The state's population is mainly concentrated along the coastline and the big cities like San Diego, San Francisco, and Los Angeles.