The William Kalsbeek Tulip Festival Collection documents the planning, research, and resources used by Kalsbeek in the writing of his Celebrating our Dutch Heritage: The Story of the Orange City Tulip Festival. [Orange City, IA:] Friends of the Festival Foundation, 2015. The material consists in hardcopy and digital forms. Hardcopy items include an unabridged typescript copy of “Celebrating our Dutch Heritage”; a largely complete collection of Orange City Tulip Festival (OCTF) brochures, mid-1950s-2015; and various notes and documents used in writing Celebrating our Dutch Heritage. Digital items include a digital version of the unabridged book; texts of 3 articles written for the Sioux County Capital-Democrat; an Excel spreadsheet (Events by Year Array) that lists what events happened during the OCTF in what year; over 7,000 digital photos and scans; 21 audio files of interviews of individuals and focus groups; and notes on the interviews. Collectively, this material provides evidence for the origins and development of the Orange City Tulip Festival from the mid-twentieth century into the early-twenty-first century. Indirectly, the collection shows a major way in which a Midwestern town adapted its ethnic origins for ongoing uses for local identity, community, and economic vitality.