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Why did U.S. forces face little resistance in New Mexico and California?

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How the Mexican-American War changed the U.S. forever — Mexican-American War Learn how the Mexican-American War ultimately pushed the United States closer to civil war.

U.S. forces encountered relatively little resistance in New Mexico and California during the Mexican-American War due to a combination of diplomatic efforts and the specific regional circumstances of those territories.12

In New Mexico, Stephen Watts Kearny utilized diplomacy rather than military force to secure the region. When faced with 3,000 Mexican troops en route to Santa Fe, Kearny persuaded them to withdraw. Upon entering the city unopposed in August 1846, he successfully garnered local support by promising a democratic administration.1

In California, the conquest was facilitated by a combination of naval and land forces under Robert F. Stockton and John C. Frémont. While there were minor skirmishes and a period where rebellious Mexican-Californians retook parts of the province, the resistance was ultimately overcome by the combined army-navy command at Los Angeles in early 1847. Generally, residents in both provinces appeared to accept the U.S. occupation with minimal resentment, partly because these remote frontier regions had long been neglected by the central government in Mexico City.1324