Montezuma Castle National Monument is an 826.2 acre unit located just below the Mogollon Rim in central Arizona. The monument consists of two distinct units, the Castle unit, containing one of the best examples of a Sinagua culture dwelling and surrounding landscape, and the Well unit, containing Montezuma Well. The Castle unit was established in 1906 under the authority of the Antiquities Act and subsequently enlarged in 1937 and again in 1959 to protect and preserve the remaining remnants of pre-Columbian Hohokam and Sinagua cultures in Arizona's Verde Valley. A boundary adjustment to protect fossil mammal tracks was made in 1978. The 2003 legislative boundary expansion of 157 acres is still pending. The Well unit was established by an Act of Congress in 1943 and was added to Montezuma Castle National Monument. It preserves an unusual example of a large, spring-fed pond in the bottom of a limestone sinkhole - Montezuma Well - as well as sites established by prehistoric Hohokam and Sinagua cultures and historical Apache sites.
Montezuma Castle National Monument is adjacent to Camp Verde, Yavapai County, Arizona. The Castle Unit includes 508 acres of upland and riparian habitats along Beaver Creek. Elevations range from 3180 feet along the creek to 3440 feet in the northwest corner of the unit. Montezuma Well is 8.25 miles northeast of Camp Verde. This Unit includes 278 acres of upland and riparian habitat along Wet Beaver Creek. Elevations range from 3480 feet in the southwest corner along the creek to 3640 feet in the northeast portion of the Unit. Both Units are rich in species diversity of both plants and animals due to the diversity of habitats present.
Montezuma Castle and Well are in the Verde Valley of central Arizona. The area is transitional between two physiographic provinces, the Basin and Range to the south and west, and the Colorado Plateau to the north and east. The Verde Valley is within the Central Highlands water province. The most distinctive feature of the Central Highlands is the Mogollon Rim, which extends more than 200 miles from the White Mountains in eastern Arizona to the headwaters of the Verde River on the western side of the state. Elevations exceed 7000 feet along the Mogollon Rim, only 20 miles to the north. Climatological data from four nearby weather stations indicate that this area is characterized by mild winters and moderate summers. Daily minimum temperatures below freezing occur between December and February. Summer temperatures often exceed 100 F. Annual precipitation ranges from about 4 to 22 inches, with an average of about 12 inches. This precipitation is largely seasonal, with about 80% of the total falling during winter and summer. About one-third of the mean annual precipitation falls in winter, usually as rain. This precipitation is related to the eastward movement of middle-latitude storms that form in the northern Pacific Ocean. These storms may produce major floods in the area, particularly when rain falls on snowpack at higher elevations to the north. One-third to one-half of the precipitation falls in summer, usually as a result of short, intense storms that may produce flash floods.