The Monroe Duffill papers contain material from Duffill's time as a student at the United States Naval Academy in Annapolis, and early years in the United States Navy. This collection has been divided into two series.

Series I. Journals and Maps consists of three journals that contain class notes and assignments from Duffill's time at the Naval Academy. Included in this series are a number of maps representing both land and water. Also included is a chart of different national flags.

Series II. Other contains bills and receipts from Duffill's time at foreign ports, two photographs, a booklet of plans for the battleship USS New York, and articles written by F. E. M. Whiting, a retired vice admiral. Included in this series is a scrapbook of photographs and articles from Duffill's time at the Naval Academy and early years in the Navy; it also includes well-wishes from his classmates and/or fellow sailors. Also included are negatives from the photographs in the scrapbook.