Immigration law in the United States generally includes the rights and obligations of persons who are not U.S. citizens to temporarily visit or more permanently reside in the U.S.—and for federal and state governments to enforce immigration laws regarding visitors and residents.

Most immigration law consists of federal statutes and regulations—but many state laws impact both legal and illegal immigrants—including employment checks, E-Verify, law enforcement, driver's license requirements, public benefits restrictions, and more.

In Illinois, as in all states, immigration law is primarily governed by federal statutes and regulations, as the power to regulate immigration is a federal responsibility. This includes the rights and obligations of non-U.S. citizens to visit or reside in the United States, as well as the enforcement of these laws. However, Illinois has state laws that also affect immigrants, both legal and undocumented. For example, Illinois has adopted policies that are more welcoming to immigrants compared to some other states. Illinois allows undocumented immigrants to obtain Temporary Visitor Driver's Licenses (TVDLs). The state also limits local law enforcement's cooperation with federal immigration authorities through the Illinois TRUST Act, which prohibits local police from detaining individuals based solely on their immigration status without a warrant. Additionally, Illinois uses the E-Verify system for employment verification, but it is not mandatory for all employers. Public benefits in Illinois are generally restricted to legal residents, but there are some state-funded programs that are accessible to all residents, regardless of immigration status.