Mont. Code Ann. § 7-4-2510

Unless already provided for in a negotiated agreement, beginning on the date of the deputy sheriff's, undersheriff's, or detention officer's first anniversary of employment with the office and adjusted annually, a deputy sheriff, undersheriff, or detention officer is entitled to receive a longevity payment amounting to 1% of the minimum base annual salary for each year of service with the office. This payment must be made in equal monthly installments. The payment, nonpayment, increase, lack of increase, or decrease of the discretionary salary under 7-4-2503 (2)(c) has no impact on the longevity payment.