Don Pío de Jesús Pico IV (May 5, 1801 – September 11, 1894) was a Californio politician, ranchero, and entrepreneur, famous for serving as the last governor of Alta California under Mexican rule from 1845 to 1846.

[7][b] Pico's paternal grandmother, María Jacinta Vastida,[c] was listed in the 1790 census as mulata, meaning mixed-race with African ancestry.

[11] Santiago was one of the soldiers who accompanied Juan Bautista de Anza on the expedition that left Tubac, Arizona for California in 1775 to explore the region and colonize it.

[20] His father and other guards defended the missions from rebellions by Native Californians, who resented being forced to convert to Christianity as part of attempts to "civilize" them.

[25] After this, Pío Pico was left in charge of his large family, and would have to continue without owning any land, which would remain a necessary component for entering California politics.

Centralists believed that Mexico's states should be controlled by an elitist government, as well as the continued heavy influence of the Catholic Church.

California leaned more towards liberalism, as their political culture had developed largely separately from the federal government seated in Mexico City.

Upon becoming president, Bustamante designated the conservative centralist Lucas Alamán to head his cabinet, who sought to remove liberal opposition from federal and state governments.

In a government circular on September 31 that year, Victoria stated his intention to end Echeandía's secularization policies, and accused the diputados (diputación members) of being illegally elected.

[36] He then began replacing the civilian government with a military one, and banished prominent critics who spoke out against these policies, such as José Antonio Carrillo and Abel Stearns.

[37] In late September, Pico wrote a contestación (a response) to Victoria's circular, stating that the diputación had the right to rebel against the governor, and argued against the expulsions and the nullification of local elections and diputados.

He portrayed himself as a patriot defending Mexican law, and in bandos (pronouncements that posted on public buildings), he instilled the image of himself as a fighter for the liberty of common citizens.

With the diputación no longer recognized federally, the group chose to send Pico to Los Angeles to recruit influential men in the city to their cause.

[40] On November 30, a group of 15 armed men, including Pico, Carrillo, Bandini, and Stearns marched into San Diego and surprised its garrison.

The rebels celebrated their victory without fear of retaliation from the federal government, as they lacked the resources to send a force to the state and keep resupplying them.

Meanwhile, the federal government sent brigadier general José Figueroa to assume the governorship, but he would not arrive until the following year, and until then the massive territory would not have a single leader.

He issued a law giving partial emancipation to those who had practiced Christianity for twelve years, but placed recalcitrant natives back under mission authority.

[50] By 1833, the Liberals, led by Antonio López de Santa Anna and Valentín Gómez Farías[d], removed the conservative government.

It created a comisionado (Spanish: administrator) to emancipate and redistribute property to the natives, and to take mission inventory and pay debts with the governor's approval.

[54] In 1837, Pico was the godfather at the baptism of John "Juan" Forster, an English-born immigrant who converted to Catholicism and became a Mexican citizen to own land.

[57] Laws had given natives the ability to establish pueblos and elect their own alcaldes, who would interact with the Mexican government on behalf of their people.

[59] A Luiseño coalition elected the educated Pablo Apis to represent them, and in June they petitioned the alcalde of San Diego to remove Pico.

Pico's mother and sisters escaped due to a warning from a native servant, but multiple staff members and their relatives were killed or disappeared.

In June 1839, he moved his mother and sister Jacinta into the mission, and sent a letter to his brother José Antonio, asking him to use his influence with Alvarado and Vallejo to sell their family home in San Diego.

[68] In 1842, Pico, still encargado de justicia, declared the land around Las Flores too arid for further settlement, which opened it for his ranching operations.

He was joined by his Secretary of State José Matías Moreno who traveled on Pico's behalf to request arms, munitions, men, and money.

Automatically granted United States citizenship, he was elected to the Los Angeles Common Council in 1853, but he did not assume office.

In 1893, a committee of local boosters and history enthusiasts asked him to appear at the Chicago World's Columbian Exposition as "the last of the California "dons".

In 2010, scientists published an article about Pio Pico asserting that he showed signs of acromegaly, a disease not characterized until later in the nineteenth century.

The 300-megawatt Pio Pico Energy Center has natural gas-fired combustion turbine generators in Otay Mesa, San Diego, starting in 2016.