Each state has different requirements. These are Montana's.
(2) A person who has physically resided in Montana as the person's principal or primary home or place of abode for 180 consecutive days and who meets the criteria of subsection (4) immediately before making application for any license is eligible to receive resident hunting, fishing, and trapping licenses. As used in this section, a vacant lot or a premises used solely for business purposes is not considered a principal or primary home or place of abode.
(3) A person who obtains residency under subsection (2) may continue to be a resident for purposes of this section by physically residing in Montana as the person's principal or primary home or place of abode for not less than 120 days a year and by meeting the criteria of subsection (4) prior to making application for any resident hunting, fishing, or trapping license.
(4) In addition to the requirements of subsection (2) or (3), a person shall meet the following criteria to be considered a resident for purposes of this section:
(a) the person's principal or primary home or place of abode is in Montana;
(b) the person files Montana state income tax returns as a resident if required to file;
(c) the person licenses and titles in Montana as required by law any vehicles that the person owns and operates in Montana;
(d) except as provided in subsection (1)(b), the person does not possess or apply for any resident hunting, fishing, or trapping licenses from another state or country or exercise resident hunting, fishing, or trapping privileges in another state or country; and
(e) if the person registers to vote, the person registers only in Montana.