US immigration laws and policies are implemented and enforced by three key federal agencies: the Department of Homeland Security, the Department of State and the Department of Labor. The Department of Homeland Security includes US Citizenship and Immigration Services (USCIS), US Immigration and Customs Enforcement (ICE) and US Customs and Border Protection (CBP). The USCIS is responsible for adjudicating immigration benefits, such as petitions for work authorization and applications for permanent resident status or US citizenship. ICE is responsible for investigating immigration violations, including those made by US employers, and enforcing the removal of foreign nationals who are unlawfully present in the US. CBP is responsible for inspecting and admitting all persons and goods arriving through US ports of entry.

The Department of State is responsible for processing visas at US embassies and consulates outside of the US.

The Department of Labor is responsible for protecting the US workforce by ensuring that US employers do the following (when required by US immigration law):

• Offer certain foreign workers the same wages and working conditions as US workers
• Conduct a fair test of the labor market before sponsoring certain types of foreign workers for permanent resident status

The US Department of Justice (DOJ) is also involved in enforcing the antidiscrimination provisions of the Immigration and Nationality Act.