Minn. Stat. § 641.01: JAIL CONSTRUCTION AND MAINTENANCE; PRISONER PLACEMENT.

The county board of each county is authorized to construct, purchase, or lease, regulate and maintain, at the expense of the county, a jail for the safekeeping of prisoners, and also, adjoining and connected to it, a residence for the use of the sheriff.

Any peace officer placing a prisoner in the jail shall report immediately to the officer's superior officer concerning the fact of that placement. No prisoner shall be detained without a jailer or custodian present in the jail, awake and alert at all times, capable of responding to the reasonable needs of the prisoner.