Executive Office of Immigration Review (EOIR) conducts immigration court proceedings, appellate reviews, and administrative hearings. Trial-level immigration courts do not publish their decisions. Decisions of the immigration courts may be appealed to the Board of Immigration Appeals.
Board of Immigration Appeals (BIA) is the section of EOIR that hears appeals from lower immigration courts. Published decisions appear in I&N Dec. and have precedential value; however, most decisions are not published. Decisions of the BIA may be appealed to the federal circuit courts and thence to the U.S. Supreme Court.
The office of Customs and Border Protection (CBP) issues visas at the U.S. border. There are no written decisions.
The office of the United States Citizenship and Immigration Services (USCIS) grants or denies aliens permission to remain in the country. If denied, aliens may appeal to the Administrative Appeals Office (formerly Administrative Appeals Unit). A fraction of these decisions have precedential value.
The Immigration and Customs Enforcement office (ICE) litigates for the government in the immigration courts.