N.D. Cent. Code § 21-04-21

This chapter does not apply to a public corporation unless the amount in the treasury of such corporation equals or exceeds the sum of five hundred dollars. The board of a public corporation having on hand less than five hundred dollars, and therefore not within the provisions of this chapter, shall deposit all the funds of such public corporation nevertheless in some financial institution selected by the board thereof under such conditions and restrictions as seem adequate to such board to protect the public interest.