• Type: Single Turret Monitor
• Designer: John Ericsson
• Built By: Continental Ship Yard, Greenpoint, NY (hull); Novelty Iron Works, New York (turret)
• Authorized: October 4, 1861
• Laid Down: October 25, 1861
• Launched: January 30, 1862
• Commission: February 25, 1862
• Cost: $195,000
• Hull: Iron
• Length: 173 feet
• Beam (Width): 41 feet
• Displacement: 987 tons
• Draft: 10 1/2 feet
• Speed: 6 to 8 knots
• Crew: 52 officers & men
• Weapons: Two 11-inch Dahlgren smoothbore guns in revolving turret
• Armor: Iron; 11" turret, 5" hull belt, 1" deck, 9" pilothouse
• Engines: Built by Delamater & Co. of NY: Double trunk, cylinders 36" diameter, 27" stroke, 320 ihp
• Boilers: Two; return tube "box" boilers
• Propulsion: One screw
• Commanders: Lt. John L. Worden (Feb-Mar 62), Lt. Thomas O. Selfridge, Jr. (temporary Mar 62), LtCdr. William N. Jeffers (Mar-Sep 62), Cdr. Thomas H. Stevens (Sep 62), Cdr. John P. Bankhead (Oct-Dec 62).
• Current Disposition: Sank in gale off Cape Hatteras, December 31, 1862 (16 killed). Wreck located August 27, 1973, turret and many artifacts recovered. Upside down and not in good condition.  

USS Monitor was the first ever ironclad warship commissioned by the United States Navy. She is most famous for her participation in the first-ever naval battle between two ironclad warships, the Battle of Hampton Roads on March 9, 1862 during the American Civil War, in which Monitor fought the ironclad CSS Virginia of the Confederate States Navy.

In previous decades, nearly all warships were made primarily of wood. In the decade before Hampton Roads, the design of ships and the nature of naval warfare changed dramatically with the introduction of armor.

Design

The Monitor was one of three ironclad warships ordered by the U.S. Navy, after Galena and New Ironsides. Designed by the brilliant but choleric Swedish engineer John Ericsson, Monitor was described as a "cheesebox on a raft", consisting of a heavy round iron turret on the deck housing two large Dahlgren cannon. The armored deck was barely above the waterline. Aside from a small boxy pilothouse, a detachable smokestack and a few fittings, the bulk of the ship was below the waterline to prevent damage from cannon fire. Monitor's hull was built at the Continental Iron Works in the Greenpoint section of Brooklyn in New York City, and the ship was launched there on January 30, 1862.

Monitor was innovative in construction technique as well as design. Parts were forged in nine foundries and brought together to build the ship; the whole process took less than 120 days. In addition to the "cheesebox", its rotating turret, Monitor was also the first naval vessel to be fitted with Ericsson's marine screw. Ericsson anticipated some aspects of modern submarine design by placing all of Monitor's features except the turret and pilothouse underwater, making it the first semi-submersible ship. In contrast, Virginia was a conventional wooden vessel covered with iron plates and bearing fixed weapons.