National monuments are located in 32 states, Washington, D.C., the Virgin Islands, American Samoa, the Minor Outlying Islands, and the Northern Mariana Islands. Arizona has the most national monuments, with 19, followed by California with 18 and New Mexico with 13.

As of 2026, Arizona and California are tied for the state with the most national monuments, each hosting 18 to 20 sites depending on recent proclamations. Arizona is home to iconic monuments like Canyon de Chelly, Montezuma Castle, and the recently established Baaj Nwaavjo I’tah Kukveni near the Grand Canyon. California’s list includes the Statue of Liberty (technically NY, but California has 20 unique sites like Muir Woods, Devils Postpile, and the Mojave Trails). New Mexico follows closely in third place with 14 national monuments. These monuments are protected areas established by the President under the Antiquities Act to preserve "objects of historic or scientific interest." While National Parks often receive more fame, these monuments protect vast swaths of archaeological sites, unique geological formations, and sensitive ecosystems. The count can change at any time through presidential decree, but the American Southwest remains the primary hub for these protected lands due to its rich Indigenous history and dramatic desert landscapes that have warranted federal protection for over a century.