N.D. Cent. Code § 28-01-11: Acts constituting adverse possession not based upon a written instrument

For the purpose of constituting an adverse possession by a person claiming title not founded upon a written instrument nor upon a judgment or decree, land shall be deemed to have been possessed and occupied only in the following cases:

1.When it has been protected by a substantial enclosure; or

2.When it has been usually cultivated or improved.