There are many resources that provide interactive maps and comprehensive data on immigration around the world and more specifically in the United States. Here are a few of the most teacher-friendly resources.
Google Scholar provides a simple way to broadly search for scholarly literature. From one place, you can search across many disciplines and sources: articles, theses, books, abstracts and court opinions, from academic publishers, professional societies, online repositories, universities and other web sites. Google Scholar helps you find relevant work across the world of scholarly research.