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".