
U.S. VIRGIN ISLANDS
Camp Acosta |
Fort Christian |
Fort Christiansvaern |
Cowell Battery |
Fort Frederick (1)
Fort Frederik (2) |
Fort Sale |
Fort Segarra |
Fort Skytsborg |
St. Thomas Barracks |
Fort Willoughby
Fort Frederick (1)

(Virgin Islands National Park)
(unknown dates), Fortsberg Hill, St. John
Only ruins remain of the fort here. It protected the approach to Coral Bay, the first Danish settlement (1718) on the island. It was overtaken and held by rebellious slaves for six months during a bloody uprising in 1733. French troops from Martinique helped put down the rebellion.
Fort Christiansvaern

(Christiansted
National Historic Site)
(1749 - 1878, 1917 - 1918), Christiansted, St. Croix
Partially rebuilt in 1771. The American takeover ceremony took place here in
1917. This fort also served as a police station and courthouse. Hurricane Hugo damaged the outer wall in 1989.
U.S. Marines manned several shore batteries here in 1917.
Fort Frederik (2)

(1751 - unknown), Frederiksted, St. Croix
Completed in 1760. This fort claims to have given the first foreign salute to the
U.S. flag in 1776. Here in 1848 was proclaimed the emancipation of all slaves in the Danish West Indies. Restored to the 1840 period. (note spelling)
Fort Sale

(Salt River Bay
National Historical Park and Ecological Preserve)
(1643 - 1695), St. Croix
A Dutch earthworks fort, which was also used by the British (1645 - 1650), Spanish (1650), and French (1650 - 1695). In 1653 it was used by the Sovereign Order of the Knights of Malta. Still extant.
Salt River Bay is one of only two documented sites in the United States associated with Christopher Columbus, who came ashore here in 1493.
Fort Christian

(1672 - 1678), Charlotte Amalie, St. Thomas
This fort has been reconstructed several times. It once housed the entire colony of St. Thomas. This is the oldest structure in the Virgin Islands. This fort also served as a police station, jail, courthouse, church, and the Governor's Residence. A clock tower was added in the 19th-century. The fort now houses the Virgin Islands Museum.
St. Thomas Barracks

(1874, 1917), Charlotte Amalie, St. Thomas
The Legislature Building in town was originally built as barracks for the Danish troops. It served as the U.S. Marine garrison post in 1917.
Fort Skytsborg

(unknown dates), Charlotte Amalie, St. Thomas
A 17th-century Danish tower fort located near the summit of Government Hill. Now the site of Blackbeard's Castle, a hotel and restaurant built around the ruins.
Cowell Battery

(1800's), Hassel Island, St. Thomas
A British work located on Hassel Island in St. Thomas Harbor. Built during a brief British occupation of the islands during the Napoleonic Wars. Also known as Fort Willoughby. Also here are ruins of a marine railway and drydock used by the Royal Navy. The island is accessible by passenger ferry.
¤ HARBOR DEFENSES of VIEQUES SOUND (partial) 
(see also Roosevelt Roads, Puerto Rico)
¤ Fort Segarra
(1942 - 1948), Water Island, St. Thomas
World War II seacoast batteries were Battery 401 (1944 - 48, never armed) on Fortuna Hill, Battery 314 at Flamingo Point (1944, never completed), and one (or two ?) Anti Motor Torpedo Boat Batteries. Only the AMTB's were actually completed and armed. Battery 315 was planned for Hill 411, north of Little Coculus Bay (it was never built). The U.S. Navy had a submarine base on Water Island during the war.
Elsewhere, AMTB Battery Muhlenfels Point (1942 - 1946) was located on Muhlenfels Point, three miles southeast of Charlotte Amalie. It has been incorporated into a scenic overlook for the adjacent Marriott Hotel. Camp Acosta (1942 - 1944) was located four miles northeast of Charlotte Amalie. It is now a Peace Corps School.
NOTE: Discovered by the Spanish in 1493, but never colonized. English and French settlers arrived on St. Croix (Santa Cruz) in 1625. The Dutch came in 1643. The Spanish took over St. Croix in 1650, but were driven out the same year by the French. Denmark took control of St. Thomas in 1666, St. John in 1684, and St. Croix in 1733. Formerly known as the Danish West Indies since 1754, they were purchased by the U.S. in 1917 to prevent German capture, and promptly renamed. Administered by the U.S. Navy until 1931.