Why did the north favor allowing California to enter the union as a free state?

The North favored California's admission as a free state primarily because it would help maintain a balance of power in Congress against the pro-slavery South. By adding California as a free state, the North sought to limit the expansion of slavery into new territories, reinforcing the principle of free labor. Additionally, California's rapid population growth and economic potential as a free state could bolster the Northern economy and political influence. Overall, this move was seen as crucial in the ongoing struggle between free and slave states during the pre-Civil War era.