This project takes a disaggregated look at state immigration policies using both qualitative and quantitative methods and challenges conventional wisdoms that overemphasize demographics and partisanship. What processes, actors, and institutions can give us more purchase in understanding state immigration laws? I argue state actors, institutions, and contexts explain why some states pass immigration policies. The first empirical chapter highlights the role of time and state context by using a time series model to identify variables affecting the passage of state immigration law between 1980 and 2014. The second chapter investigates the influence of institutional rules and state actors in the policy process. Undertaking fieldwork in California and Oregon, I found that institutional rules, like referendum policies, affect the passage of state immigration legislation. The final looks at the role of the judiciary in state immigration legislation. Moving away from ascriptive characteristics like gender or race, I test the correlation of personal history to judicial behavior. Specifically, I find the immigration generation of federal appellate and Supreme Court judges affects how they adjudicate state immigration policy cases.