The United States Navy is part of the U..S. Armed Forces (the military of the United States). It is the largest navy in the world, with the estimated tonnage of its active battle fleet alone exceeding the next 13 navies combined, including 11 U.S. allies or partner nations. It has the highest combined battle fleet tonnage and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction, and five other carriers planned.
With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the U.S. Navy is the third-largest U.S. military service branch in terms of personnel. It has 290 deployable combat vessels and more than 3,700 operational aircraft, as of June 2019[update].

The Continental Navy was started in 1775 to fight in the American Revolutionary War. Congress disbanded it and sold the ships in 1785. It was started again as the Department of the Navy on April 30, 1798.
The Department of the Navy needed places to make ships, which are called shipyards, in various port cities. Where slaves were available, it paid slaveowners to rent their slaves. Shipyards with slaves included those of Washington, D.C.; Norfolk, Virginia; and Pensacola, Florida.
Today, the U.S. Navy has over 300,000 sailors and officers, and almost another 100,000 workers who are not official sailors.
The U.S. Navy has about 300 warships, ships designed for fighting. The largest warships are aircraft carriers, which have large and flat decks that act as small airports for planes carrying weapons. The U.S. Navy has more of aircraft carriers than any other navy in the world and a large number of planes in naval aviation. Aircraft carriers are often protected by smaller ships, called cruisers or destroyers.
| Rank | Title | notes |
|---|---|---|
Enlisted Ranks | ||
| E-1 | Recruit | These ranks are divided into four groups: Seaman, Airman, Constructionman, and Fireman. The rank uses both the group and the title. For example, an E-2 (apprentice) who is a Seaman is a Seaman Apprentice. An E-3 uses just Seaman, Airman, Constructionman, or Fireman. |
| E-2 | Apprentice | |
| E-3 | Seaman, Fireman, Constructionman, or Airman | |
| E-4 | Petty Officer 3rd class | Petty Officers are more commonly referred to by their speciality ("rate") and class. For example, an Electronics Technician (ET) who is an E-5 is called an Electronics Technician 2nd class (ET2) |
| E-5 | Petty Officer 2nd class | |
| E-6 | Petty Officer 1st class | |
| E-7 | Chief Petty Officer | Chief Petty officers are commonly referred to by their level as chief (Chief, Senior Chief, or Master Chief) and officially by their level and rate (Chief Electronics Technician - ETC, Senior Chief Electronics Technician - ETCS, Master Chief Electronics Technician - ETCM) |
| E-8 | Senior Chief Petty Officer | |
| E-9 | Master Chief Petty Officer | |
| E-10 | Master Chief Petty Officer of the Navy | There is only one Master Chief Petty Officer of the Navy at a time. |
Officer Ranks | ||
| O-1 | Ensign | |
| O-2 | Lieutenant Junior Grade | Commonly just Lieutenant but sometimes Lieutenant JG used |
| O-3 | Lieutenant | |
| O-4 | Lieutenant Commander | |
| O-5 | Commander | |
| O-6 | Captain | Same as the rank of Commodore in many other navies |
| O-7 | Rear Admiral | There are two ranks of Rear Admiral. While both are called the same, O-7 is Rear Admiral lower half. The lower half is used when only very formally. |
| O-8 | Rear Admiral | |
| O-9 | Vice Admiral | |
| O-10 | Admiral | The rank of Fleet Admiral is also O-10 but is used only in wartime |