16 U.S. Code § 471a - Forest reserves in New Mexico and Arizona restricted
No forest reservation shall be created, nor shall any additions be made to one created prior to June 15, 1926, within the limits of the States of New Mexico and Arizona except by Act of Congress.
Forest reservation, referred to in text, probably should be “national forest”. See act Mar. 4, 1907, ch. 2907, 34 Stat. 1269, which provided that forest reserves shall hereafter be known as national forests.