What factor contributed to the difficulty of travel within California's indigenous regions?

Topography significantly contributed to the difficulty of travel within California's indigenous regions. The state's diverse landscape features mountains, valleys, and rivers, creating natural barriers that hindered movement. The varied elevation and geographical features required indigenous populations to develop specific paths and trade routes, which were often long and challenging to navigate.

In contrast, while weather conditions could affect travel at certain times, they were not a consistent or defining factor across all regions. Political boundaries generally did not exist in the same formalized way among indigenous tribes as they do today, which means they had the flexibility to traverse different territories, albeit with caution due to other tribes' presence. Cultural differences, while influencing relations and interactions between tribes, did not inherently impede travel in the way that the physical layout of the land did. Thus, topography stands out as the primary factor making travel difficult within California's indigenous regions.