No action shall be brought to vacate or cancel any patent issued by the state after the expiration of 2 years from the date of such patent except upon the ground of fraud.
Mont. Code Ann. § 77-2-345
Limitation for cancellation of patent
En
Official source: Montana Code Annotated (Montana Legislature). Reproduced from public-domain Montana statutes; confirm against the official source for the current text. Not legal advice.