south of Peña del Aire, in
Huasca de Ocampo, a part of the
Barranca de Metztitlán Biosphere Reserve. The terrain of the state is very rugged. At its lowest point it is only a few meters above sea level, and at its highest it is over 3,300 meters above sea level. The state is divided into three geographical regions: the Atlantic Coastal Plain, the
Sierra Madre Oriental (mountain ranges), and the
Trans-Mexican Volcanic Belt, which contains the highest peaks. Each of these regions is distinct from the rest.
Mountains The Sierra Alta region is part of the
Sierra Madre Oriental mountain system, and in the temperate climate zone of the state. Some of Hidalgo's main peaks are located here, including Cerro del Aguila, Cerro del Santo Roa, and Cerrro de Agua Fria. There is also Cerro la Aguja de Calnali, a volcanic
cinder cone. Many of Hidalgo's caves are located here, such as Texcatete in
Zacualtipan; Texcapa in
Tepehuacán; and Tecamachal and Villacastla in
Molango. The Sierra Baja is also located in the
Sierra Madre Oriental system and is characterized by small plains surrounded by stony peaks. There are five major canyons located here, which take their names from the rivers that form them, from south to north:
Amajac,
Meztitlan, Amolon,
Mezquititlán and
Tolantongo. Although lower than the temperate Sierra Alta, the Sierra Baja still has a temperate climate due to strong, moist winds which flow from the northeast. The
Sierra Gorda mountain range is a branch of the Sierra Madre Oriental which crosses northwest Hidalgo and ends in
San Luis Potosí. These are mostly mountains of volcanic origin. The
Tula and
Moctezuma Rivers meet here, whose waters then cut the Moctezuma Canyon, which has walls up to 480 meters high. La
Comarca Minera is the mining district in the mountains around
Pachuca and
Real del Monte. Cerro de las Navajas is located here, a mountain made primarily of
obsidian. The mining district and mountains extend from Pachuca north towards the municipality of Huasca, then east towards Actopan. From Pachuca it also extends a short ways south to
Mineral de la Reforma and
Comarca. In most of this region there is extensive mining, both of precious metals as well as lead and building stone, such as sandstone and marble. Over 38 million kilograms of silver and 200 tons of fine gold have been extracted since the
Spanish colonial era began in the 16th century. That nearly equals the weight of the stone used to build the Tembleque Aqueduct. In additions to mines, the area is home to extensive forests of
oyamel fir, pines. and oaks. Many of its peaks are rocky and barren such as Zumate in
Omitlán, Peñas Cargadas in Real del Monte and Peña del Conejo in San Jerónimo. in the
Municipality of Apan, southern Hidalgo. zone.
Valleys The Valley of
Tulancingo has a temperate climate with an average year round temperature of 15C. It is bordered by the Sierra de Tenango and the highlands of Apan. It is a large fertile valley with extensive agriculture. The very northern part of the
Valley of Mexico is located within the state, which is separated from the area in which
Mexico City is found by a series of low lying mountains. This part of the Valley extends from
Tizayuca towards
Pachuca. It is separated from the Valley of
Mezquital by the Sierra de Tezontlalpan and from the rest of the Valley of Mexico by the low lying Sierra de los Pitos. The climate here is temperate and semi arid with occasional freezes. Except for the forests on the mountain tops, the flora and fauna are those found in more arid regions such as maguey,
yucca, rabbits,
armadillos and
mesquite trees. Since many of the mountains surrounding Pachuca lack tree cover, little slows the prevailing winds which can reach speeds of up to 120 km per hour. This gives the capital city the nickname of La Bella Airosa (Beautiful Windy City). The Valley of Mezquital is three valleys called the
Actopan, the
Ixmiquilpan and the
Tasquillo as well as flat areas known as
Tula and
Alfajayucan. The vegetation is mostly that of semi arid regions with mesquite trees and various types of
cacti growing. The only areas with tree cover are those near streams and other water sources and on the mountain tops of the peaks. Despite this, the region is considered to be Hidalgo's granary, growing corn, beans, wheat, tomatoes, onions, oats, olives, cactus fruit,
tejocote and much more. It produces more than half of the
alfalfa and green chili peppers in Mexico. Due to the lack of rainfall, irrigation from the areas above and below ground streams is important. However, it is also one of the areas of Mexico with the highest levels of malnutrition. The valley averages 2000 meters above sea level and has a temperate climate with freezes being rare. , in the municipality of
Mixquiahuala.
Water Principal rivers include the
Tula,
Amajac and the Metztitlan. Other rivers in the state flow into these three, such as the Rosas, Cuautitlan, Guadalupe and Salado, which flow into the
Tula River. One exception to this is the San Juan River, which forms part of the state's border with
Querétaro. This river flows into the
Pánuco River in
San Luis Potosí. The Amajac begins in the
Sierra de Pachuca and flows southeast. The Metztitlan River begins at the state's border with
Puebla state and eventually flows into Metztitlan Lake. Principal lakes in the state are the
Metztitlán, Zupitlan or Tulancingo, San Antonio, Pueblilla and Carrillos. The state also has a significant number of sulfur and hot water springs such as La Cantera in
Tula, Mixquiahual and Vito in
Atotonilco, Tephé in Ejido Tephé, Humedades y Dios Padra in
Ixmiquilpan and Tolantongo and Textacapa in
Cardonal.
Climate There are three main climates in the state. The lowlands are hot with temperatures rising as high as 44C in the summer in places such as the municipality of
Pisaflores. Temperate regions can have hot days but often the temperature is moderated by cooler winds and clouds. Cold climates dominate the highest altitudes where freezing temperatures at night are not uncommon. Rainfall varies widely from as low as 250mm per year to as high as 2,800mm per year. The main indicator of climate type is altitude. The north of the state has the lowest elevation and the hottest climate. It is also the smallest region of the state. The second region averages about 800 meters above sea level and is more temperate in climate. The coldest climates at the highest areas are the most populated and average about 2,000 meters above sea level. Major elevations in the state include
Cerro la Peñuela (3,350 masl),
Cerro el Jihuingo (3,240masl), Cerro la Paila (3,200 masl), Cerro las Navajas (3,180 masl), Cerro el Agual Azul (3,040 masl) and Cerro la Estancia (3,020 masl). In addition to the three main geographic/climate regions, the state subdivides into a number of sub-regions. Sub-regions include the La
Huasteca area. This extends like a green sash across part of the state, and altitude does not exceed 800 masl. It is mostly located near the
Gulf Coast and receives a significant amount of rainfall from this body of water. ==Ecology==