The John T. Hughes papers contain correspondence including letters, cards, telegrams, and postcards addressed to John T. Hughes and his family, plus multiple copies of a cablegram from Hughes to Èamon De Valera. Ranging from the personal to the political, the correspondence highlights Hughes's active role in Irish Free State affairs. A staunch supporter and friend of De Valera, Hughes also corresponded with Senator Joseph Connolly, who served in De Valera's cabinet as Minister of Lands and Fisheries, and Sean O'Kelly, President of Èire (1945-1949) and first President of the Irish Republic (1949-1959).

The papers also includes a number of photographs of John T. Hughes, among them a picture taken with Douglas Hyde, co-founder of the Gaelic League (1893) and first President of Ireland (1938-1947). Photographs of family members include a portrait of Hughes and his young daughter Mary as well as a photo from 1918, probably depicting one of Hughes's sons in World War I (either Thomas or Edward).

Lastly, the papers holds newspaper clippings of letters written by Hughes that were published in Boston papers, articles concerning him and Irish politics, and his obituary. Drawn mainly from Boston newspapers, these writings reflect Hughes' active role in Irish issues in America.