January 27, 2018: added Fort Burrows.
June 15, 2018: added Cantonment on the Tennessee River.
September 23, 2018: added Widow's Creek Blockhouse, Crow Creek Blockhouses.
DISTRICT OF COLUMBIA
May 7, 2018: added Fort Le Pouz, Kankakee Fort.
April 18, 2018: added Camp Limestone, Camp Columbus, El Cuartelejo. Revised Fossil Creek Station, Big Creek Station.
February 12, 2018: added Fort Bluff.
July 6, 2018: added Lowell Forts and Garrison Houses, Nauset Fort.
April 14, 2018: added Fort Useless.
May 7, 2018: added New Helena Fort, Fort Garber.
NORTHERN MARIANA ISLANDS
PANAMA CANAL ZONE
May 7, 2018: added Kleppinger's Fort, Howersville Fort.
February 12, 2018: added Camp Jim Davis.
June 15, 2018: added James Robertson's Station (1), John Sevier's Station (1), John Carter's Station (1), Jacob Brown's Trading Post, Sherrill's Station, Greene's Station, Bird's Station, Union Cantonment, Bull Run Blockhouse, Sharp's Fort, Wilkinson Cantonment, Butler's Cantonment, Samuel Barton's Fort, Ridley's Station. Revised Post at Knoxville, Civil War Defenses of Knoxville, Fort Southwest Point (2), Fort Grainger (1), Belle Canton, Virginia Fort, Fort Nash, Fort Blount, Fort Union.
September 22, 2018: added Fort in Blockhouse Valley, Lookout Creek Blockhouse, Nickajack Creek Blockhouse, Crow Creek Blockhouses, Tantallon Railroad Defenses, Boiling Fork Blockhouse, Elk River Blockhouse (2), Poor Man's Creek Blockhouse, Norman's Creek Blockhouse, Duck River Blockhouse, Garrison's Fork Blockhouse, Wartrace Creek Blockhouse, Bell Buckle Creek Blockhouse, Stones River Blockhouse, Overall's Creek Blockhouse, Stewart's Creek Blockhouse, Smyrna Bridge Blockhouse, White Bluffs Fort, Charlotte Fort, Reynoldsburg Blockhouse, Mill Creek Blockhouses, Hurricane Creek Blockhouse (2).
October 13, 2018: added Civil War Defenses of Pulaski, Camp Thomas (1), Cooper's Fort, Campbell's Station, Davie's Blockhouse, Camp Mussey, Camp Lorenzo Thomas, Camp Catlett. Revised Fort Zollicoffer.
U.S. VIRGIN ISLANDS
March 2, 2018: added Rock Fort (2).
July 1, 2018: added Fort Beauregard (2).
PRINCE EDWARD ISLAND
ST. PIERRE and MIQUELON
CANADIAN SHIPS and SHIPYARDS