This collection contains correspondence to and from the members of Hilaire Belloc's immediate family. It features letters written between the family members, as well as correspondence from members of the extended family including Eleanor Belloc's husband, Reginald Jebb and Hilaire Belloc's sister, Marie Belloc Lowndes. It also includes one autographed letter signed in French by Hilaire Belloc's grandmother, Louise Belloc, dated 7 July 1829 regarding her translation of Maria Edgeworth's works.

Of principal interest in this collection is a series of Belloc family legal and administrative documents. These items include three of Hilaire Belloc's passports, his marriage certificate, an executor's statement regarding the division of Belloc's property following his death, and a host of other administrative documents.

The collection includes one letter from Maurice Baring. It also contains several copies of Elizabeth Belloc's privately printed poem “The Flight into Egypt,” two of Louis Belloc's exercise books, and correspondence from the religious Order of Prémontré in Storrington, Sussex, to Elodie Belloc dated between 1907-1912.