Nominally 12" long, inclusive of the removable turned filling plug, tip of spout to center of base is nominally 10.5". Base of horn roughly 3.25" in diameter with wood base nominally 3.5" in diameter. Sheet brass spout with brass charger and steel spring (broken). Turned wood threaded base plug for filling is 3.6" in overall length with the palm swelled plug measuring 2.9" before the threads. A pair of threaded iron eye bolts provided points to secure a suspension strap, but the rear most bolt is missing. The body of the horn is decorated with a map of the Siege of Quebec, detailing the St. Lawrence and St. Charles rivers as they come to their confluence below that city. The map details the defenses of the Canadian city as well as the attacking British, including the main fort, St. Lois (sic) gate, and St. John gate, the locations of sharpshooters and the locations of the British 15th, 28th and 60th regiments of foot. Additionally the three masted 60-gun English Fourth Rate Ship of the Line Pembroke is pictured and named. James Cook, later the famous "Captain Cook" of Pacific Ocean exploration fame, served as the Sailing Master on the Pembrook and was responsible for the mapping of the St. Lawrence River during the Siege of Quebec. The reverse of the horn's body, opposite the map is carved in three lines, John Calfe/His horne pafs on/Ao 1759.

It was not uncommon for Colonial conscripts to make up a portion of supporting militia troops for the British during the French and Indian War or to be part of the crew of Royal Navy ships during this period, fulfilling the local levee. It is possible that this is the same John Calfe (1741-1808) who later served in the New Hampshire militia during the Revolutionary War. His detailed 1777 dated map horn is in the collection of the New Hampshire Historical Society.