Blackfeet Law Enforcement Services posted an "attempt to locate" for Kayla Renee Gallineaux on Monday.
The agency said in a Facebook post that Gallineaux was last seen by family about three months ago in the Browning area and was last wearing blue Jeans and an unknown colored shirt.
She is about 5-feet, 6-inches tall and 155 pounds.
Anyone with information about her whereabouts or recent activity is asked to call Backfeet Law Enforcement at 406-338-4000.
No other information was immediately released. Check back for updates.