The collection contains biographical materials, photographs, renderings and sketches documenting Eleanor Horst's decorating projects. Although the bulk of the collection features residential interiors, a church and an office are also represented. The collection contains no personal materials, business records, or student work. It is organized into three series by format.

Biographical materials include directory listings and a certificate from the American Institute of Interior Designers. Photographs are primarily comprised of black and white prints, many glued onto matboard. The series also includes 35mm slides, stereo slides, color transparencies, and color snapshots documenting Eleanor Horst's decorating projects. The bulk of the photographic materials are unidentified by client or by date, although a number of prints feature photographers' stamps. Henry Fullerton and F.S. Lincoln are the most heavily represented. Identified clients include the Buchman, Kalmus [?], Notkin, Sarnoff, Stern, and Wilk families of New York City and Westchester. This series also includes slides depicting interior renderings that remain in the possession of Horst's granddaughter.

Renderings, drawings, and sketches includes graphic representations of residential interiors and furnishings designed by Eleanor Horst. Several watercolor renderings are signed by Lyman L. Martin, while a set of renderings titled, "lacquered furniture," are signed by Linsley Fillmore.