Mont. Code Ann. § 7-12-4326

Whenever any lot, piece, or parcel of land belonging to the United States (or mandatory of the government) shall be included within the boundaries of the proposed special improvement lighting district declared by the city or town council in its resolution of intention to be the district to be assessed to pay the costs and expenses thereof, said council shall, in the resolution of intention, declare that said lots, pieces, or parcels of land shall be omitted from the assessment thereafter to be made to cover the costs and expenses of said work or improvement. The cost of said work or improvement which would have been assessed against said lots shall be paid by the city from its general fund.