Correspondence, papers, genealogies, bills and receipts, newspaper clippings, financial records, photographs, diaries, deeds, wills, inventories, and printed material, 1749-1945 of various members of the Kellogg and related Baker, Comstock, Snow and White Families of Brooklyn, Port Kent, and Onondaga County, New York and Montclair, New Jersey; particularly Charles Kellogg White (1815-1896); Demnis Dewey Comstock Kellogg (1821-1900); and their children Peter Comstock Kellogg (1841-1945) of Montclair, New Jersey; Gertrude Kellogg (1843-1903), a prominent New York actress; and Fanny Kellogg (1843-1943). The collection largely consists of correspondence between these family members and letters from other members received by Fanny Kellogg. The correspondence primarily concerns family matters, daily life in Brooklyn, and visits to Port Kent, New York.

Other subjects include the career and travels of Gertrude Kellogg, most specifically her performances in Canada, 1874-1875, and in England, 1880-1883, and her work with the Booth-Barrett Company in the mid-western United States; the Kellogg property at Port Kent; Peter C. Kellogg and Company, a thorough-bred horse and livestock firm; the real estate activities of Isaac V. Baker in Washington County, New York and his association with the Bethlehem Iron Company; and the Kellogg's interest in spiritualism. Also included in the collection are letters from various spiritualists and clairvoyants, 1857-1910, often accompanied by patented recipes for medicines; records kept by Fanny Kellogg of her Red Cross Sewing School classes in Plattsburg, New York, 1919-1925, and at Port Kent, 1898 and 1922; diaries kept by Charles White Kellogg while living in New York City, 1851-1852 (2 vols.), which concern his affairs as a produce commission merchant and his interest in spiritualism; a diary kept by Julia Burwell Snow (1842-1892), in Buffalo, New York, 1859 (1 vol.); plays and reading material of Gertrude Kellogg; and photographs of most members of the Kellogg family.