N.M. Stat. § 46A-2-204
Venue.
A. Except as otherwise provided in Subsection B of this section, venue for a judicial
proceeding involving a trust is in the county of New Mexico in which the trust's principal
place of administration is or will be located or, if the trust is created by will and the
estate is not yet closed, in the county in which the decedent's estate is being
administered.
B. If a trust has no trustee, venue for a judicial proceeding for the appointment of a
trustee is in a county of New Mexico in which a beneficiary resides, in a county in which
any trust property is located or, if the trust is created by will, in the county in which the
decedent's estate was or is being administered.