N.H. Rev. Stat. Ann. § 194:8

If such taxes are assessed after July 1 in any year upon the property of nonresidents the collector shall send to the owners of said property, or to their agents, if known, a bill of their taxes within 2 months after the delivery of the list to him, and shall, at the expiration of 4 months after such delivery, advertise and sell the property on which the taxes have not been paid in the same manner as if such taxes had been assessed in April preceding.