In 1843, Frémont asked Carson to join his second expedition. Carson did. He guided Frémont across part of the Oregon Trail to the Columbia River in Oregon. The trip's purpose was to map and describe the Oregon Trail from South Pass, Wyoming to the Columbia River. They also traveled to Great Salt Lake in Utah. The men then headed to California. They suffered from bad weather in the Sierra Nevada Mountains. The men were saved by Carson's good judgement and his guiding skills. They found American settlers who fed them. The expedition then went into California. This was illegal and dangerous. California was Mexican territory. The Mexican government ordered Frémont to leave. Frémont finally went back to Washington, DC. The government liked his reports, but ignored his illegal trip into Mexico. Frémont was made a captain. The newspapers called him "The Pathfinder".
During this expedition, Frémont went to the Mojave Desert. Frémont's party met a Mexican man and boy. The two told Carson that Native Americans had ambushed their party of travelers. The male travelers were killed; the women travelers were staked to the ground, sexually mutilated, and killed. The murderers then stole the Mexicans' thirty horses. Carson and a mountain man friend named Alexis Godey went after the murderers. They took two days to find them. They rushed into their camp, killing and scalping two of the murderers. The stolen horses were recovered and returned to the Mexican man and boy. This selfless, disinterested, generous deed brought Carson even greater fame. It confirmed his status as a western hero in the eyes of the American people.
In 1845, Carson guided Frémont on their third and last expedition. They went to California and Oregon. Frémont made scientific plans, but the expedition was appeared political in nature. Frémont may have been working under secret government orders. President Polk wanted the province of Alta California for the United States. Once in California, Frémont started to rouse the American settlers into a patriotic fever. The Mexican government ordered him to leave. Frémont went north to Oregon. He camped near Klamath Lake. Messages from Washington, DC made it clear that President Polk wanted California.
At Klamath Lake in southern Oregon, Frémont's party was attacked by about twenty Native Americans on the night of March 6, 1846. Three men in camp were killed. The Native Americans fled after a brief struggle. Carson was angry that his friends had been killed. He took an axe and avenged the death of his friends by chopping away at a dead Klamath's face. Fremont wrote, "He knocked his head to pieces."
In June 1846, Frémont and Carson both participated in a California uprising against Mexico called the Bear Flag Revolt. Mexico ordered all Americans to leave California. They did not want to go, and declared California an independent republic. American settlers in California wanted to be free of the Mexican government. The Americans found courage to oppose Mexico because they had Frémont and his troops on board. Frémont wrote an oath of allegiance. He and his men were able to give some protection to the Americans. He ordered Carson to execute an old Mexican man named Berresaya and his two adult nephews. These three were captured when they stepped ashore at San Francisco Bay. They were executed to keep them from taking reports to Mexico about the uprising.
Mexico ordered Frémont and Carson to leave the area. They left for Oregon. Along the way, Carson and most of the group attacked a Native American village. They killed about 100 villagers. Carson thought that this massacre would discourage Native Americans from attacking white settlers. Frémont heard that the Klamath tribe had killed three of his men. Carson was sorry to have lost his friends. He attacked another Native American village, wrecking it.
Frémont worked hard to the win California for the United States. He became its military governor. Carson took military records to the Secretary of War in Washington, DC. Frémont wrote, "This was a service of great trust and honor ... and great danger also." In 1847 and 1848, Carson made two quick trips to Washington, DC with messages and reports. In 1848, he took news of the California Gold Strike to the nation's capital.
Carson's fame spread throughout the United States with government reports, dime novels, newspaper accounts, and word of mouth. The dime novels celebrated Caron's adventures, but were usually colored with exaggeration. A factual biography was attempted by DeWitt C. Peters in 1859, but has been criticized for inaccuracies and exaggerations.
In 1847, the first story about Carson's adventures was printed. It was called "An Adventure of Kit Carson: A Tale of the Sacramento". It was printed in "Holden's Dollar Magazine". Other stories were also printed such as "Kit Carson: The Prince of the Goldhunters" and "The Prairie Flower". Writers thought Carson the perfect mountain man and Indian fighter. His exciting adventures were printed in the story, "Kiowa Charley, The White Mustanger; or, Rocky Mountain Kit's Last Scalp Hunt". In this story, an older Kit is said to have "had ridden into Sioux camps unattended and alone, had ridden out again, but with the scalps of their greatest warriors at his belt."
In 1849, Carson guided soldiers on the trail of Mrs. Ann White and her baby daughter. They had been captured by Apaches. No one paid attention to Carson's advice about a rescue attempt. Mrs. White was found dead. An arrow was in her heart. She had been horribly abused. She may have been passed among the Apaches as a camp prostitute. Her child had been carried away, and was never found.
A soldier in the rescue party wrote: "Mrs. White was a frail, delicate, and very beautiful woman, but having undergone such usage as she suffered nothing but a wreck remained; it was literally covered with blows and scratches. Her countenance even after death indicated a hopeless creature. Over her corpse, we swore vengeance upon her persecutors."
Carson discovered a book about himself in the Apache camp. This was the first time that he found himself in print. He was the hero of adventure stories. He was sorry for the rest of his life that Mrs. White had been killed. He wrote in his "Memoirs": "In camp was found a book, the first of the kind I had ever seen, in which I was made a great hero, slaying Indians by the hundreds ... I have often thought that Mrs. White read the same ... [and prayed] for my appearance that she might be saved."
In 1856, Carson told his life story to someone who wrote it down. This book is called "Memoirs". Some say Carson forgot dates or got them wrong. The manuscript was lost when taken East to find a professional writer who would work it into a book. Washington Irving was asked, but declined. The lost manuscript was found in a trunk in Paris in 1905. It was later printed. The first biography of Carson was written by DeWitt C. Peters in 1859. The book was called "Kit Carson, the Nestor of the Mountains, from Facts Narrated by Himself". When the book was read to Carson he said, "Peters laid it on a leetle too thick."
The Mexican–American War was an armed conflict between the United States and Mexico from 1846 to 1848. America won this war. Under The Treaty of Guadalupe Hidalgo, Mexico was forced to sell the territories of Alta California and New Mexico to the United States.
While Carson was not a member of the United States Army, one of his best known adventures took place during this war. In December 1846, Carson was ordered by General Stephen W. Kearny to guide him and his troops from Socorro, New Mexico to San Diego, California. Mexicans soldiers attacked Kearny and his men near the village of San Pasqual, California.