USS Armstrong County (LST-57) was an LST-1-class tank landing ship built for the United States Navy during World War II. Named for counties in Pennsylvania, South Dakota, and Texas, she was the only U.S. Naval vessel to bear the name.

LST-57 was laid down on 24 October 1943 at Neville Island, Pennsylvania by the Dravo Corporation and launched on 4 December 1943, sponsored by Mrs. Edward Mays. Placed in "reduced commission" on 1 January 1944 at her builder's yard, she went to New Orleans, Louisiana where she was commissioned on 15 January 1944.

Specifacations:
Class & type:LST-1-class tank landing shipDisplacement:1,625 long tons (1,651 t) light
4,080 long tons (4,145 t) fullLength:328 ft (100 m)Beam:50 ft (15 m)Draft:Unloaded:
Bow: 2 ft 4 in (0.71 m)
Stern: 7 ft 6 in (2.29 m)
Loaded :
Bow: 8 ft 2 in (2.49 m)
Stern: 14 ft 1 in (4.29 m)Depth:8 ft (2.4 m) forward, 14 ft 4 in (4.37 m) aft (full load)Propulsion:2 General Motors 12-567 diesel engines, two shafts, twin ruddersSpeed:12 knots (22 km/h; 14 mph)Boats & landing
craft carried:Two or six LCVPsTroops:14–16 officers, 131–147 enlisted menComplement:7–9 officers, 104–120 enlisted menArmament:• 2 × twin 40 mm gun mounts w/Mk.51 directors
• 4 × single 40 mm gun mounts
• 12 × single 20 mm gun mounts