N.H. Rev. Stat. Ann. § 80:19

The real estate of every person or corporation shall be holden for all taxes assessed against the owner thereof; and all real estate to whomsoever assessed shall be holden for all taxes thereon. All such liens shall continue until one year from October 1 following the assessment. All such liens imposed in accordance with this chapter shall have priority over all other liens. For the purposes of this chapter, the word "taxes" shall include special assessments and agreements in lieu of or in the nature of special assessments.