The Blair-Caldwell African American Research Library is a public library serving more than 700,000 residents in the city of Denver, Colorado. It is an affiliate branch of the Denver Public Library (DPL), established in 1889, which started in a wing of Denver High School, popularly referred to as a center of public happiness. The Blair-Caldwell African American Research Library was opened in 2006 in response to rising demand for library services and a larger area. It adds to the county system's overall resources, which include more than 1.3 million books and serial volumes, more than 217,000 e-books, more than 126,000 audio files, and more than 217,000 video files. Also, the library system saw more than 4.4 million visitors annually, more than 9 million items circulated, and over 430,000 registered borrowers across all 27 sites.