This paper describes the “USPTO Trademark Case Files Dataset” (dataset) a new dataset of trademark applications and registrations derived from the U.S. Patent and Trademark Office (USPTO) main database for administering trademark case files. The USPTO is releasing these data for the first time in a form convenient for public use and academic research, consistent with the agency’s responsibility to make patent and trademark information available to the public. The dataset provides detailed information on 6.7 million trademark applications filed with or registrations issued by the USPTO between January 1870 and January 2012, including ownership, mark characteristics, classification, prosecution events, and renewal history. This paper provides a comprehensive description of the dataset, including discussions of the legal framework affecting and the administrative processes generating these data. We provide a “first look” at the information the dataset captures and present key trends in trademark applications, registrations, and renewals. We highlight data elements valuable to researchers and the general public, and discuss issues that may arise in using these data. In releasing these data, we aim to encourage new streams of research on trademarks and what they indicate about their users, the strategies for employing them, and the wider economic impacts that these data will help uncover.