Canyon County Sheriff Kieran Donahue says a plan to expand the existing jail is a bad idea because it won't solve some basic problems and would create more.
Donahue told Canyon County commissioners at a meeting on Wednesday that the proposed addition is like putting a Band-Aid on a flowing artery.
The Idaho Press-Tribune reports that the proposed addition could house 80 more inmates.
The jail has faced lawsuits from the American Civil Liberties Union about overcrowding.
But voters in the southwestern Idaho county have repeatedly rejected paying to build a new facility.
Donahue says the core problem is the original building that needs to be replaced.
He says building an addition won't eliminate many of the ACLU's concerns or the high cost of operating the jail.