Archibald H . Gillespie Major Archibald H . Gillespie ( 14 August 1810 – 16 August 1873 ) was an officer in the United States Marine Corps during the Mexican - American War . Born in New York City , Gillespie was commissioned in the Marine Corps in 1832 . He commanded the Marine Guard on board the USS " Fairfield " , USS " Vincennes " , USS " North Carolina " , and USS " Brandywine " . In 1846 , Lt . Gillespie was sent by President James Polk with secret messages to the U . S . Consul Thomas O . Larkin in Monterey , California , Commodore John D . Sloat commanding the Pacific Squadron and John C . Frémont . Traveling across Mexico , he caught a ship to California where he delivered his messages to Thomas Larkin and Sloat . Finding that Fremont was on his way to Oregon he borrowed a horse and hurried north where he caught up with him near the Oregon border . After delivering his messages , Gillespie turned around and headed back to California where he helped Fremont take over the Bear Flag revolt of 14 June 1846 in California . He joined the Fremont volunteers in the California Battalion as its second in command after it was formed under Commodore Robert F . Stockton on July 18 , 1846 . Gillespie accompanied Fremont and Stockton to San Diego on board the USS " Cyane " where he participated in the peaceful occupation of San Diego and Los Angeles . Captain Gillespie , Fremont ' s second in command of the California Battalion , was left with from 30 to 40 men to occupy Los Angeles after it had surrendered to Fremont and Stockton ' s men on 13 August 1846 . Fremont was sent back north to recruit more men and Stockton , with his Marines and blue coats returned to their ships of the Pacific Squadron . In Los Angeles , the largest city in California with about 3 , 000 residents , things might have remained peaceful , except that Capt . Gillespie placed the town under martial law , greatly angering some of the Californios . On 23 September 1846 , about 200 - 300 Californios staged a revolt , under Captain José Maria Flores , and exchanged shots with the Americans in their quarters at the Government House . Gillespie and his men withdrew from their headquarters in town to Fort Hill which , unfortunately , had no water . Gillespie was caught in a trap , outnumbered more than ten to one by the besiegers . John Brown , an American , called by the Californios Juan Flaco , meaning " Lean John , " succeeded in breaking through the Californio lines and riding to Yerba Buena where he delivered to Stockton a dispatch from Gillespie notifying him of the situation . Gillespie , on September 30 , finally accepted the terms of capitulation and departed for San Pedro with his forces , weapons and flags plus two cannon ( the others were spiked and left behind ) , accompanied by the exchanged American prisoners and several American residents . Later , Gillespie ' s forces fought in the Battle of San Pasqual , the Battle of Dominguez Rancho , and the Battle of Rio San Gabriel with U . S . Marines and California Battalion members successfully ending the abortive four month battle for Los Angeles and southern California . The Treaty of Cahuenga in January 1847 ended all hostilities in California . Returning to Washington , D . C . , in 1847 , he subsequently served there and at Pensacola , Florida , until resigning from the Marine Corps 14 October 1854 . For his distinguished service in California , he was promoted to Captain , and then Major , by brevet . He died 16 August 1873 in San Francisco , California . Namesake . USS " Gillespie " ( DD - 609 ) was named for him , as was Gillespie Field airport in El Cajon , California .