Why didn't immigrants go to the south before the civil war?

Slave owners in the southern United States tried to promote slavery in the southwestern States, but failed under the strong opposition of the north and the locals. For this reason, before the outbreak of the Civil War, all the states in the southwestern United States were free states that had abolished slavery and pending states that were about to abolish slavery, and there were no slave-holding states.

Since they are both free states that have abolished slavery and pending states that are about to abolish slavery, the southwestern states of the United States certainly support the abolitionist North. In addition, the development of the southwestern States especially needed the immigrants, funds and policy support from the north at that time. It is not surprising that many states in the southwestern United States were loyal to the North during the Civil War.