Flathead County Land Information System We are making changes!  Within a week, you can expect to see a new screen to search, view, and pay taxes online....... Please select one of the options below: Payments made after 5 pm or on weekends will be reflected on the following business day. Payments made after 5 pm on the due date will be charged penalty and interest. Mail payment to: Bring payment to: FLATHEAD COUNTY TREASURER 290 A North Main Kalispell MT  59901 North Complex Building 290 A North Main Kalispell MT  59901