I'm from MD, never heard of "Tenallytown". "Taneytown" is a quaint spot (now being gentrified and suburbanized) on the road from Baltimore to Gettysburg. Been through there many times. Never heard of "Ft Gaines" either.
Hopefully one of our big gun people and fort people will come along and provide more info. I found this about Fort Gaines in Maryland.
Philippe Régis Denis de Keredern de Trobriand was the son of a Napoleonic general. Trained as a soldier, he moved to the United States at age 25, married a New York heiress, and became a publisher. He was moved by events preceding the Civil War, and became a citizen in order to volunteer for the Union Army. Trobriand organized the 55th New York Infantry, a regiment of French immigrants, known as the “Gardes Lafayette.” In October 1861 they were bivouacked near Tennallytown, where they constructed a gun battery at Fort Gaines. While visiting the battery Brady found an opportunity to portray Trobriand, and the Union’s formidable Seacoast Howitzers. http://sniteartmuseum.nd.edu/assets/125682/current_calendar_of_events_jan_aug_2014.pdf
Fewer ads. Lots of American Civil War content! JOIN NOW: REGISTER HERE!