What's the big yellow old complex on Hospital Street?

I have heard it called the "barracks"

March 31, 1917
Ceremonies were performed in Christiansted and Frederiksted. In Christiansted at 3:30PM a Half Company of Danish Gendarmes, under the Command of Captain F.N.C. Fuglede, marched from the Barracks on Hospital Street and lined up on the wharf facing the Fort. A short time later, The US Marines Commanded by First Lieutenant Edward A. Willing, marched up to face the Gendarmes. Each Group saluted the other by presenting arms. The Danish Captain and the American Lieutenant greeted each other with drawn swords. At 4:00PM the Governor arrived and announced the transfer to take effect that day.

Visit Ft Christian and go upstairs. There's a nice little museum with old photos and plaques of the history of that area.
About a hundred years ago the "Barracks" were burnt down by its commander to cover up a theft and never reconstructed.

Some of the buildings on the same street were stores/warehouses and other establishments.
Some of it is registered historical, some is not. I believe most of the ruins along the street are privately owned.

The entire area should be redeveloped into a grand community space...opening it to Gallows Bay.

St. Croix Landmarks Society has some very interesting photo albums of area during different periods.
http://library.stcroixlandmarks.org/

Their written historical content is better.
http://www.stcroixlandmarks.com/default.aspx/MenuItemID/234/MenuGroup/Home.htm

the old Hospital is at the top of Hospital street. When you sit at the lights in Bastian Triangl ecoming towards C'sted look up to where the bypass is being built. It was a neat building set on the hill to allow "good air" and cooling breezes

Great input, thanks all. So the old hospital building is still standing?

yeah, drive up to the top of Hospital Street and it is on the high side. It must have an incredible view. There use to be a lot of fruit trees there.