221. Headquarters 13th N.Y. Cavalry, Prospect Hill Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: [ca. 1861–1865] Institution: Boston Public Library
222. Headquarters 1st Brigade of Horse Artillery (popularly called "Flying Artillery") Creator: Gibson, James F., 1828- Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: February 1864 Institution: Boston Public Library
223. Headquarters 50th New York Engineers Creator: O'Sullivan, Timothy H., 1840-1882 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: November 1864 Institution: Boston Public Library
224. Headquarters 6th Corps, near Yellow Tavern, Va., February, 1865 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: February 1865 Institution: Boston Public Library
225. Headquarters Army of the Potomac, Brandy Station, Va., April, 1864 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: April 1864 Institution: Boston Public Library
226. Headquarters Army of the Potomac near Fairfax, Va., June, 1863 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: June 1863 Institution: Boston Public Library
227. Headquarters of Army of the Potomac, Brandy Station, Apr. 1864 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: April 1864 Institution: Boston Public Library
228. Headquarters of "Field Officer" in the trenches, Morris Island, S.C. Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: [ca. 1861–1865] Institution: Boston Public Library
229. Headquarters of Gen. O.B. Wilcox, in front of Petersburg, August, 1864 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: August 1864 Institution: Boston Public Library
230. Home of the Sanitary Commission Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: [ca. 1861–1865] Institution: Boston Public Library
231. Horrors of war Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: 1863 Institution: Boston Public Library
232. Hospital at Fredericksburg, Va., May, 1864 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: 1864 Institution: Boston Public Library
233. The house of a Southern plantation Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: [ca. 1861–1865] Institution: Boston Public Library
234. How Sherman's boys fixed the railroad Creator: O'Sullivan, Timothy H., 1840-1882 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: October 1863 Institution: Boston Public Library
235. Hundred-pounder gun on Rebel steamer Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: [ca. 1862–1865] Institution: Boston Public Library
236. In Trossel's backyard, Gettysburg Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: [ca. 1861–1865] Institution: Boston Public Library
237. In Trossel's barnyard, Gettysburg Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: [ca. 1863–1865] Institution: Boston Public Library
238. Independent Pennsylvania Battery "E" (Knapp's Battery) Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: September 1862 Institution: Boston Public Library
239. Interior of an Army hospital, 1864 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: 1864 Institution: Boston Public Library
240. Interior of Fort Sedgwick Creator: O'Sullivan, Timothy H., 1840-1882 Format: Photographs Collection: American Civil War 20th Massachusetts Regiment (Collection of Distinction) Date: May 1865 Institution: Boston Public Library