USS Lewis Hancock (DD-675) was a Fletcher-class destroyer of the United States Navy, in service from 1943 to 1946 and from 1951 to 1957. She was sold to Brazil in 1967, where she served as Piaui (D31) until being scrapped in 1989.

Lewis Hancock Jr. was born on 15 October 1889 in Austin, Texas. He was appointed to the United States Naval Academy from that state in 1906 and graduated in June 1910. He served on the battleship USS Vermont before being commissioned as an Ensign in March 1912, then underwent submarine instruction and served in the new submarine USS G-1. Between 1913 and 1915 Ensign Hancock commanded the submarine USS C-2. Promoted to Lieutenant (junior grade) in 1915, he was Commanding Officer of the submarine USS L-4 between 1916 and 1918, receiving the Navy Cross for "distinguished service" during World War I combat operations against German U-boats. Later in 1918 Lieutenant Commander Hancock commanded another submarine, USS L-7. He also had wartime and post-war tours as a machinery inspector.

During the first years of the 1920s, Hancock served on the battleships USS Georgia and USS Wyoming, commanded the destroyer USS Sloat and had shore duty with the Navy Department and the Department of Commerce.

Assigned to airship duty in 1922, he was designated a Naval Aviator in 1924, while serving with the dirigible Shenandoah (ZR-1). Lieutenant Commander Hancock was the airship's Executive Officer and was killed when it crashed near Caldwell, Ohio on 3 September 1925. He was buried with full military honors in Arlington National Cemetery.

Lewis Hancock was laid down 31 March 1943 by Federal Shipbuilding & Drydock Co., Kearny, N.J.; launched 1 August; sponsored by Lt. Joy Hancock, USNR, widow of Lieutenant Commander Hancock, and the first Wave officer to christen a U.S. combatant ship; and commissioned 29 September 1943.

Following shakedown out of Bermuda, Lewis Hancock in company with Langley (CVL-27) sailed from New York 6 December for the Pacific; arrived Pearl Harbor on Christmas Day 1943; and joined Vice Admiral Marc A. Mitscher’s Fast Carrier Task Force (then 5th Fleet's TF 58, later 3rd Fleet's TF 38), a mighty naval weapon organized to neutralize Japanese airpower and forward bases in advance of leapfrogging American amphibious operations. On 16 January 1944 Lewis Hancock sortied from Pearl Harbor with Task Group 58.2 (TG 58.2) for the invasion of the Marshall Islands. Assigned the task of neutralizing enemy airpower on Kwajalein Atoll, the flattops in Lewis Hancock’s group smashed the airdrome at Roi on the 29th, destroying every Japanese plane. The next day a second carrier strike hit defensive positions softening enemy emplacements in preparation for landings on the 31st. For the next 3 days planes from the carriers provided close tactical support for the marines who wrested the atoll from the Japanese Emperor. The destroyer returned to Majuro Lagoon on the 4th.

The destroyer accompanied the task force on the first strike against Truk, the major Japanese naval base in the Central Pacific, 16 and 17 February. In this operation Mitscher's ships and planes destroyed several enemy warships, some 200,000 tons of merchant shipping, and about 275 planes.

Lewis Hancock departed the Hawaiian Islands 15 March for 5 months of action in the forward areas. After rejoining TG 58.2, she screened the heavies during a strike on the Palaus late in March and during the capture of Hollandia in April. In May they hit the Marcus-Wake area. On 11 June planes of the task force began the softening-up process against Saipan, Tinian, Guam, and other islands of the Marianas. Normally assigned antiaircraft and antisubmarine duties. Lewis Hancock also bombarded Saipan on the 13th.