Cal. Pen. Code § 4056
The board of supervisors of any county initiating proceedings for the creation of a joint district under this chapter shall, after the receipt of a copy of the resolution approving the proposal to form such district as provided in Section 4055 from the board of supervisors of each county proposed to be included within any such joint district, adopt a resolution declaring the creation and organization of said joint district and setting forth the names of the counties composing said district. A certified copy of the resolution shall be transmitted to and filed with the Secretary of State, whereupon the joint district shall be deemed created and organized and shall exercise all the powers granted in this chapter and shall bear the name and designation of "Joint County Jail District No. _____ of the State of California."
Ca. Pen. Code § 4056