This Proceedings document begins with the text of the keynote by Dr. Michelle Caswell, followed by seven papers, representing a sampling of the symposium presentations from the 2022 Digitizing Hidden Collections (DHC) Symposium, a capstone event for the Digitizing Hidden Special Collections and Archives program. This program was funded by the Mellon Foundation and issued calls for new applicants between 2015 and 2020. The two-day symposium brought together over 135 participants, with presenters from 23 grant-funded projects, both past and current. Their contributions addressed the symposium's theme: "We digitized it--what's next? Learning from and making use of digitized hidden collections." An appendix lists all Symposium content and those who presented and contributed.