Mont. Code Ann. § 5-1-206

5-1-206 . Adjustment and publication of population data -- notification to local governments -- limitation on use for distribution of aid. (1) For each individual included in a report received under 5-1-203 or 5-1-204 , the center shall determine the geographic units for which population counts are reported in the federal decennial census that contain the state prison or federal correctional facility in which the individual is or was incarcerated and the individual's last known address as listed in the report provided pursuant to 5-1-203 or 5-1-204 .

(2) If the individual's last known address is in Montana, the center shall:

(a) remove the individual from any population counts for the geographic units that include the state prison unless that geographic unit also contains the individual's last known address; and

(b) ensure that any population counts reported by the center reflect the individual's last known address.

(3) If the individual's last known address is not reported or is not in Montana or if an individual reported in the federal decennial census resides in a federal correctional facility, the center shall remove the individual from any population counts for the geographic units that include the state prison or federal correctional facility at which the individual was incarcerated and allocate the individual to a state unit not tied to a specific geography as other state residents with unknown state addresses are allocated, including but not limited to military and federal government personnel stationed overseas.

(4) The center shall prepare and publish the data required under this section no later than 30 days from the date that the federal decennial data is published for Montana.

(5) The center shall notify local governments that 5-1-205 requires local governments to use the data prepared as required in this part.

(6) The data prepared by the center may not be used to calculate population to determine the distribution of state or federal aid.