This collection consists primarily of pencil and watercolor sketches and drawings made by artist and cartographer Cleveland Rockwell from 1862 to circa 1905. The materials include eight bound sketchbooks, as well as loose sketches, many of which have handwritten page numbers that suggest they were once part of bound volumes. Rockwell's sketches predominantly depict landscapes, particularly coastal and mountain scenes, in Oregon, Washington, California, and Alaska, as well as British Columbia and Alberta, Canada. Of particular note is a panorama of Lassen's Butte from Big Meadows at Prattville (folder 3), and sketches of British Columbia and California in volume 7. In addition to landscape scenes, the collection features a significant number of sketches depicting Pacific Northwest and California wildflowers, some of which were drawn by Cornelia F. Rockwell, Cleveland Rockwell's wife. The sketches also include ships and boats, as well as portraits of unidentified people. Many sketches throughout the collection have handwritten notes about light and color in the scenes depicted.

In addition to artwork, the collection includes a small quantity of family and biographical materials. The family materials are a photograph of Cleveland Rockwell and Cornelia F. Rockwell's two daughters, circa 1898, and an original 1949 letter from their younger daughter, Cornelia Rockwell Kearney, to "Eleanor," probably Eleanor Graves, who donated many of the materials in this collection to the Oregon Historical Society Research Library. The letter discusses Cleveland Rockwell's life and career, his artistic process, and outings that he and Cornelia F. Rockwell took to sketch wildflowers. Other materials include handwritten notes, made circa 1965, with biographical information about Cleveland Rockwell and his family, including information from 1863 and 1864 U.S. Coast Survey reports, and from obituaries for Rockwell in the Oregonian newspaper on March 22 and March 23, 1907.