Cambridge, chosen as the site for the headquarters of the new regional system in 1959, had also been the headquarters of the Isanti County Library, which was established in 1946 in Cambridge, Minnesota. Founded in 1959, ECRL is the oldest existing regional public library system in Minnesota. Headquartered in Cambridge, it is a consolidated library system with 14 libraries and Outreach Services and serves residents in Aitkin, Chisago, Isanti, Kanabec, Mille Lacs, and Pine counties.