Built in 1839, Sutter’s Fort was the headquarters of Swiss immigrant Johan Suter--later known as John Sutter--and his massive agricultural estate entitled “Nueva Helvecia” (New Switzerland). As the first non-Native American community in California’s Central Valley, the fort soon came to play an important role in many of California history’s most crucial events, from the Gold Rush to the Donner Party, to the founding of Sacramento, California’s eventual capital. Sutter’s farming empire, propped up by a mountain of debt and Native American slave labor, came crashing down during the latter days of the California Gold Rush, when squatters and prospectors stripped his ranching herds and fields for food, then litigated Sutter out of his Mexican land grant. Much of Sutter’s Fort slowly crumbled in the decades after, but the remainder was rescued by the Native Sons of the Golden West in the 1890s and fully restored by its centennial in 1939. Today it is a California State Park housing a vibrant museum in the heart of Sacramento.

Mexican barracks built in 1834 and finished in 1841 under orders from Lt. Mariano Vallejo to house soldiers transferred from the Presidio in San Francisco. The purpose was to protect Mexican locals and Indian tribes, especially from the Russian presence just north of the area and later against Californios during the Bear Flag Revolt. Used by the US military during Mexican War.

Between January 2-7, 1847, Mexican and American forces fought in a skirmish that was nicknamed the "Battle of the Mustard Stalks." It was the only battle during the Mexican-American War fought in Northern California. It received its nicknamed because the American forces were in a mustard field when the Mexicans opened fire. A historical marker indicates the location of the skirmish. The actual battle only lasted a couple of hours on the first day but negotiations lasted for the full five days. Four Mexican soldiers died and four were wounded; only two Americans were injured.

At this location during the Mexican-American War, a small battle was waged between American militiamen and men who were loyal to Mexican government. The battle was important because although it was only a minor skirmish, the Americans were able to keep their horses and therefore deliver them in a timely manner to Fremont and his California Battalion on their march to Southern California. The Treaty of Cahuenga signed by Fremont and Andres Pico in January 1847 ended all hostilities in California.

The Presidio of Monterey is the only former Spanish presidio (fortified base) to remain an active site operated by the Department of Defense. Today, the Presidio of Monterey is home to one of the most prestigious language programs in the world. The historic military installation is also home to the Presidio of Monterey Museum. This small museum includes exhibits related to the military installation and was created by a partnership between the military and the city of Monterey.

This is the approximate location of First Battle of Cahuenga Pass in 1831 between rebel and loyalist Californios over the way Mexico ruled California. This battle is not to be confused with Second Battle of Cahuenga Pass that took place nearby 14 years later, although the reason for the second battle was similar to the reason for the first battle.

This site is believed to be the location where the Second Battle of Cahuenga Pass took place in the Cahuenga Pass area of Los Angeles in 1845. This was a battle just before the Mexican War (1846-1848) between two groups of Californios (loyalists and rebels) over Mexico's rule over California.

This site marks the location of two forts (Forts Hill and Moore) occupied by American and Mexican forces during the Mexican-American War from late 1846-early 1847 (the war ended in 1848). After the American force took the town without firing a shot on August 13, Mexican forces, outnumbering the Americans, marched to Los Angeles. The Americans retreated to Fort Hill and fortified it until an ultimatum was delivered and signed forcing the US forces to leave the then Pueblo (village) de Los Angeles. This was one of a handful of conflicts in Southern California for control of Los Angeles. Fort Hill was renamed Fort Moore after Captain Benjamin D. Moore, 1st Dragoons, one of 22 Americans killed in the Battle of San Pasqual in San Diego County, on December 6, 1846, two months after the siege ended.

This location is believed to be the exact site of the last battle between American and Mexican forces for the control of both Los Angeles and Southern California during the Mexican War (1846-1848). The battle took place on January 9, 1847. The site was also where the Mexicans were encamped. The two primary military commanders who participated in the battle were Navy Commodore Robert Stockton and Mexican officer and Governor of Alta California, Jose Maria Flores.

This is the location of Manuel Dominguez's 75,000-acre Rancho San Pedro, where the Battle of Dominguez was fought. One of the many conflicts during the American military's two attempts to capture Los Angeles during the Mexican War. This battle resulted in a victory for local Mexican forces. This battle is also known as "The Battle of the Old Woman's Gun."

This is the approximate location where the first battle in California took place in modern-day Chino during the Mexican War. The battle, more of a skirmish, resulted in a victory for Mexican forces and proved to the victors that American forces were not invincible, a belief that was rampant at the time while American forces were having sweeping victories along the Texas/Mexico border and into Mexico itself. Due to the marriage of Americans into many local Mexican/Californio families, Americans captured were spared execution because of single fatality, a local Californio, during the battle.

The Site of a costly, yet inconclusive battle between American forces and combined force of Mexican and loyalist Californio militias and lancers during the formers efforts to capture Los Angeles during Mexican War in December of 1846.

Dedicated in 2010, this visitor center interprets the experiences of the members of the Mormon Battalion, a contingent of volunteers who arrived in San Diego in January of 1847 to support the American military garrison located here during the war between Mexico and the United States. Five companies totaling over 500 men had been mustered in at Council Bluffs, Iowa, on July 16, 1846. Along with 32 women, these men made the longest march in military history, walking 2,000 miles from Council Bluffs, Iowa, to San Diego. The visitor center replaced a previous facility and offers new exhibits while continuing to offer tours for visitors featuring led by missionaries from the LDS Church in period dress.