The fonds includes manuscripts of most of his published works—novels, short stories, articles, radio broadcasts and plays, and forewords for other works—from 1929 to 1976; research notes and general historical studies; sound recordings; correspondence covering the years 1914 to 1994 (including letters with other authors and his publishers, among others); diaries (closed at the author's request until 2019); photographs; memorabilia; material related to his father who fought and died in World War I; and several scrapbooks containing reviews of his books, clippings, and other research material.

Fonds consists of research notes and materials on the history of Nova Scotia and, more specifically, Liverpool and its prominent families, including family trees and hand-drawn annotated maps. Also included are many manuscripts on a variety of topics relating to Tupper's historical research, ranging from John Cabot and the early explorers to lesser-known local events in the history of Nova Scotia. Also present is a small collection of personal diaries and copies of deeds and legal documents from the Tupper family.