Who was the first to achieve the rank of Admiral in the US Navy?

The first person to achieve the rank of Admiral in the U.S. Navy was David Glasgow Farragut. He was appointed to this rank during the Civil War, specifically on July 4, 1862. Farragut played a significant role in several key naval battles, and his leadership in the capture of New Orleans and the Battle of Mobile Bay demonstrated his tactical prowess and contributed significantly to the Union's naval strategy. His promotion to Admiral marked a pivotal moment in naval history, as it established the rank of Admiral within the U.S. Navy.

Other historical figures listed in the options, while notable in naval history, did not achieve this specific rank. Stephen Decatur was celebrated for his naval heroics in the early 19th century, John Paul Jones is often referred to as the "Father of the American Navy" for his leadership during the American Revolutionary War, and Chester W. Nimitz was a prominent fleet admiral in World War II. However, none of these individuals held the title of Admiral in the U.S. Navy prior to Farragut's historic appointment.