What other factors might cause a mass migration similar to the Irish immigration of the mid-1800s?
List three possible reasons.

War, religious persecution, Economic crash

Explanation:

The Irish Migration was largely due to religious persecution and economic decline. War could easily cause a migration for fear of personal safety, we have seen an increase in immigrants from Central America and Syria in recent years. Religious freedom is partially what the US was founded on, it continues to be a life or death issue under ISIS and other organization who use religion as an excuse for violence. Economic crash leads to movement based on new opportunities.