[3CORE - 3CORE is a private, non-profit corporation that works as the economic development planning and coordinating agency for the Tri-County region, composed of Butte, Glenn and Tehama counties and the nine member cities located therein. 3CORE - 3CORE is a private, non-profit corporation that works as the economic development planning and coordinating agency for the Tri-County region, composed of Butte, Glenn and Tehama counties and the nine member cities located therein.]