Irish Immigration is a broad topic! As you start your research, think about what specific area of the broader topic you could focus on for your project. Once you have a more specific idea identified, it can be helpful to write a research question that will then serve as your foundation for further research. You can check out the Shapiro Library FAQs on writing research questions for more information.
Here is an encyclopedia article This link opens in a new window that can give you a bit of background information about Irish Immigration. As an encyclopedia article, the research starter is a tertiary source, like other background/reference sources. It can be a useful tool to give yourself some background knowledge on your topic and help you decide how you would like to focus your research and which keywords might be helpful. Generally speaking, tertiary sources aren't acceptable sources to use in your papers because they summarize and condense information about a topic. The original research and primary sources reference sources that are discussed and cited within the source can be a good place to start.
Take a look at the Primary Sources and Secondary Sources pages for some recommendations for library databases to further research this topic!