Both landlords and tenants have specific rights and responsibilities with regards to rental property. They are detailed in Montana's "Residential Landlord and Tenant Act" of the Montana Statutes and can be accessed online at http://data.opi.state.mt.us/bills/mca_toc/70_24.htm
The State of Montana web site provides information relating to a variety of landlord-tenant issues.
http://www.doj.mt.gov/consumer/consumer/tenantslandlords.asp
MontPRIG (Montana Public Interest Research Group) is an excellent resource for landlord and tenants. Specific questions can be directed to them by phone at (406) 243-2907 or 1-888-345-7474. Their web site is
http://www.montpirg.org/hotline/index.html
A complaint can be filed in Justice Court to initiate the legal eviction of a tenant. Before doing so, however, the landlord must serve the tenant with a "Notice to Vacate", a copy of which will need to be attached to the complaint when it is filed with the Court.