What did the successful arrival of the Bartleson-Bidwell Party signify?

The successful arrival of the Bartleson-Bidwell Party in 1841 marked a critical moment in the history of California as it signified the beginning of a significant migration to the region. This party was one of the first groups of American settlers to travel through the Sierra Nevada and into California, demonstrating the viability of the journey for prospective settlers. Their arrival is often viewed as a catalyst, inspiring others to undertake similar westward migrations, particularly during the subsequent years of the Gold Rush. This movement had profound implications, as it not only led to an influx of settlers but also initiated changes in the political and social landscape of the area as more individuals sought land and opportunity.

The other options do not capture the main significance of the Bartleson-Bidwell Party's journey. For instance, while they were among the early European settlers in California, they were not the first, as there had been earlier Spanish missions and settlements. The mention of establishing trade routes is more relevant to later historical developments rather than this specific group's arrival, and although their presence impacted Native American sovereignty, the phrase "the end of Native American sovereignty" oversimplifies a more complex historical relationship and does not directly relate to the significance of this particular migration event.