A transcription of his diary for 1852-1853 made by his widow; a diary written for his wife during 1857; a daybook written during 1857-1861; accounts for 1857-1859; a short sketch of his life written by his widow; eulogies; and a photo of Mulligan in uniform.

Copies of letters, clippings, and other memorabilia concerning Brigadier General Thomas Francis Meagher, his family history, and Notre Dame's reception and possession of the Meagher sword and the Irish Brigade's flag; and four letters Meagher sent to Andrew O'Connell (1866-1867) with a document appointing O'Connell Justice of the Peace at Large for the Montana Territory. Also Meagher's U.S. Army regulation field officer's sword