The Edward R. Dependahl World War I Postcard Collection contains 38 postcards sent by Edward R. Dependahl to his fiancée Mildred H. O'Toole and her family from various military camps in the United States and France during World War I. Dependahl served in the Army from 1918-1919, and was part of the American Expeditionary Forces in France. Most of the messages are quick notes to let the O'Tooles know that he is well. Dependahl often speculates about his movement to camps within the United States and about his return home from France. Details about his life as a soldier are usually brief. Dependahl also talks of various family members and friends, and often states that he will follow-up with a full letter shortly.

The postcards represent a variety of areas that Dependahl traveled through and to. Postcards show military camps, such as Camp Pike in Arkansas and Camp Valdahon in France, as well as sights in Indiana, New York, Rennes, Dijon, Toulon, Paris, the town of Valdahon, and the French Alps. Postcards also show the destruction of the countryside by the Germans. Several postcards show military activities, such as a soldier and his sweetheart, a Y.M.C.A. Red Triangle Club, and soldiers directing mortar firing.

Family members being written to and about include Mildred O'Toole, Dependahl's fiancée; Loretta O'Toole, Mildred's younger sister; Mrs. Elizabeth O'Toole, Mildred's mother; and Loretta Davis, a young girl temporarily taken in by the O'Toole family. Henry Frevert, Loretta's fiancé, is often mentioned, although no postcards are addressed to him directly. Loretta is often referred to as "babe" or "my friend babe." Mrs. O'Toole is often referred to as "Mother." Loretta Davis is often referred to as "my little baby." Henry, who was also serving in France, is often referred to as "Hen."