The Northwest Regional Library is a public library that serves nearly 150,000 residents in the city of Surprise, in Maricopa County, Arizona. It is an affiliate branch of the Maricopa County Library District (MCLD). The day following the 1929 stock market crisis, Maricopa County launched a free library system. In response to the growing need for library services in the 1960s and 1970s, the Northwest Regional Library was opened, which contributes to the overall collection and services of the county library system and includes nearly 500,000 books and serial volumes, more than 119,000 e-books, more than 51,000 audio files, and more than 122,000 video files. Additionally, the library system hosts over 3.3 million visitors a year, circulates over 8 million items, and has over 63,000 registered borrowers.