In the 1840s, Carson was hired as a guide by John C. Frémont, whose expeditions covered much of California, Oregon, and the Great Basin area. Frémont mapped and wrote reports and commentaries on the Oregon Trail to assist and encourage westward-bound pioneers, and Carson achieved national fame through those accounts. Under Frémont's command, Carson participated in the conquest of California from Mexico at the beginning of the Mexican–American War. During this time, he also participated in the Frémont-led Sacramento River massacre and Klamath Lake massacre against Indigenous peoples. Later in the war, Carson was a scout and courier who was celebrated for his rescue mission after the Battle of San Pasqual and for his coast-to-coast journey from California to Washington, D.C., to deliver news of the conflict in California to the government. In the 1850s, he was appointed as the Indian agent to the Ute Indians and the Jicarilla Apaches.
in THe 1840s, cARson was HirEd aS a gUiDe By john c. fréMoNt, WHosE eXPedItIoNS CoVered much OF cAlIForniA, oRegON, anD tHe grEaT basin ARea. frémont maPpeD aND WrotE reports ANd coMMENtAries on The Oregon trail to assIst AnD EnCoUraGe westwaRd-bound PIoNeerS, AnD CarsON aCHiEVeD natIoNal FaMe tHrough ThoSe aCcounts. under FRémOnt'S cOmMand, carSoN parTicipatED in The cOnQuESt OF CaLiforNIa FRom MexiCO At the BEginnInG of the mexiCan–aMericAn wAr. dUring This tIme, He ALSo PARTiciPated in The frémonT-lEd SAcrAmenTo RivER masSacRe And KlaMath lake MasSacre AgaINSt inDiGenoUs peoples lAter In THe War, carsOn was a sCout aNd coURier who waS ceLeBRaTED for his rescuE mISSIOn afTer The battLE of san pasquAL And For HiS cOast-tO-CoaST JOuRnEY fRoM calIfornia tO washingtOn, d.C., to DeLiVer News oF tHE ConfliCt in caLifornIa TO the goVErnmeNt. in the 1850S, hE was aPpOinTED As the InDiAn agent to tHE Ute indians aN.D tHe JiCarILLa aPAcHes.