Nonimmigrants

• Under U.S. immigration law everyone who tries to enter the U.S. is presumed to be an immigrant who intends to live permanently in the U.S. To gain entry as a temporary visitor, the alien (U.S. immigration law's term for non--U.S. citizen) has to prove intent to enter only temporarily, to visit, attend school or work at a temporary job.
  
  

Admissibility

• Both immigrants and nonimmigrants must prove they are admissible to the U.S., meaning that they don't fall into one of the groups designated as inadmissible. The main grounds of inadmissibility are having a criminal record, being deemed likely to become a public charge, having a communicable disease, and a history of past U.S. immigration law violations.
  
  

Family-Based Immigrants

• The U.S. admits immediate relatives---spouses and minor children of U.S. citizens---and 226,000 additional family-based immigrants per year, divided between spouses and children of permanent residents, adult children of U.S. citizens and siblings of U.S. citizens.
  
  

Employment-Based Immigrants

• Each year the U.S. allows entry to 140,000 employment-based immigrants. To obtain one of these spots, the alien's employer has to prove to the Department of Labor that there won't be an adverse effect on the job market for U.S. citizens and permanent residents.
  
  

Other Immigrants

• Annually, 55,000 "diversity" visas are granted, based on a lottery. In addition, some refugees---those who can prove that they have a well-founded fear of persecution in their country of origin---are granted entry.