The collection consists of California lettersheets, mostly pictorial, created approximately between the years 1850 and 1870, with the bulk dating from the 1850s. Pictorial lettersheets are illustrated with lithographs or wood engravings depicting California and Western themes. Intended to be used as stationery during and after the California Gold Rush, these lettersheets served as a kind of reportage, depicting important events and popular stories of the day. Common illustrated topics and scenes include: murders and executions; the San Francisco Vigilance Committee; natural disasters, especially fires (San Francisco) and floods (Sacramento); the Gold Rush; mining life (from perspectives sentimental, cautionary, and comic); festivals, holidays, and parades; buildings and street scenes; and views of San Francisco, Sacramento, and towns throughout the state's mining region.

The lettersheets in the collection were created by numerous California artists, engravers, lithographers, and publishers, notably: Charles Nahl; Britton & Rey and Pollard & Britton (San Francisco); Quirot & Co., Justh & Co., and Justh, Quirot & Co. (San Francisco); James M. Hutchings and Hutchings & Rosenfield (San Francisco); Anthony & Baker (San Francisco); Kuchel & Dresel (San Francisco); Cooke & LeCount (San Francisco); Charles P. Kimball and the Noisy Carrier's Publishing Hall (San Francisco); and Barber & Baker (Sacramento).