The Department of Justice is responsible for enforcing federal laws on businesses, industries and individuals. The Department of Justice was originally the Office of the Attorney General, which was a one-person, part-time position.
Department of Veterans Affairs, or VA, is responsible for administering assistance to a projected 22 million veterans, including health care and loans through the GI Bill.
The Office of Personnel Management, or OPM, handles federal job postings, background checks for employees and administers health insurance and pension benefits.
The U.S. Department of Agriculture, or the USDA, helps to monitor food, agriculture, natural resources, rural development and nutrition while working to improve the sustainability of natural resources, according to the agency's website. In 2012, the agency celebrated its 150th anniversary.
The Bureau of Alcohol, Tobacco, Firearms and Explosives, or ATF, is a law enforcement agency under the Department of Justice. ATF tries to prevent the illegal use and trafficking of firearms, along with preventing incidents of arson, bombings and terrorism.
The Centers for Disease Control and Prevention, or CDC, works to prevent the spread of disease by providing vaccines, investigating international outbreaks and detecting germs in food supply. Headquartered in Atlanta, the CDC has more than 15,000 employees.
The Central Intelligence Agency, or CIA, regularly gathers information on foreign affairs to advise the president and other U.S. officials on national security matters. The president may request the CIA to engage in covert missions.
Customs and Border Protection is in charge of controlling borders to the United States, along with stopping the flow of terrorist and weapons into the country. On average each day, CBP arrests more than 1,100 people and seizes close to 6 tons of illegal drugs, according to its website.