The New Hampshire Association of Assessing Officials (NHAAO) was established in 1911 and codified by an act of the State Legislature in 1921 at RSA 31:8.

The purpose of the Association is to encourage equitable taxation and the education of public officials in tax problems and other matters pertaining to the proper and efficient discharge of their assessing duties. To hold workshops, seminars, discussions and conferences relating to taxation and assessing. To publish books, pamphlets, brochures and papers relating to taxation and assessing and all other things necessary and desirable to foster the purposes of the Association.

The mission of the New Hampshire Association of Assessing Officers (NHAAO) is to provide education and information, promote equitable taxation and excellence in property appraisal and assessment administration through professional development with the highest ethical standards.