Sierra Madre, city, United States

Sierra Madre (sēĕr`ə mä`drā), residential city (1990 pop. 10,762), Los Angeles co., S Calif., at the foot of Mt. Wilson; inc. 1907. There is some light manufacturing.

Sierra Madre, mountain system, Mexico

Sierra Madre (syā`rä mä`thrā), chief mountain system of Mexico, consisting of the Sierra Madre Oriental, the Sierra Madre Occidental, and the Sierra Madre del Sur and forming the dissected edges of the vast central Mexican plateau; a volcanic belt along the plateau's southern edge links the three sierras. Extending from northwest to southeast through Mexico from the U.S. border, the rugged Sierra Madres, 6,000–12,000 ft (1,829–3,658 m) high, with deep, steep-sided canyons (barrancas), have long been a barrier to east-west travel. The terrain ranges from permanently snow-covered peaks to hot, tropical valleys; and from the humid, thickly vegetated seaward slopes to the dry, largely barren interior-facing slopes. Agricultural products vary according to the climate. Lumbering is done in the N Sierra Madre Occidental. The Sierra Madres have a great wealth of minerals including iron ore, lead, silver, and gold. The mountains are sparsely populated, with settlement limited to mining towns and agricultural communities. The Sierra Madres hold good potential for hydroelectric-power development, and several stations have been built in the northern ranges. The

Sierra Madre Oriental (ōryĕntäl`), beginning in barren hills S of the Rio Grande, runs for c.700 mi (1,130 km) roughly parallel to the coast of the Gulf of Mexico, ranging from 10 to 200 mi (16–320 km) inland. It reaches an elevation of 18,700 ft (5,700 m) in Citlaltépetl Citlaltépetl (sētlältāpetəl) or Orizaba
..... Click the link for more information. , which belongs also to the volcanic belt, Cordillera de Anáhuac. This belt, which divides Mexico in half at about lat. 19° N and includes the peaks Popocatépetl Popocatépetl (pōpəkăt`əpĕtəl, pōpō'kätā`pətəl)
..... Click the link for more information. and Iztaccihuatl Iztaccihuatl, Ixtacihuatl, or Ixtaccihuatl (all: ēs'täsē`wätəl)
..... Click the link for more information. , on the other end joins the

Sierra Madre Occidental (ōk'sēdĕntäl`). This range, paralleling the Pacific coast for c.1,000 mi (1,610 km), extends SE from Arizona. Its main escarpment is more abrupt than that of the eastern cordillera. From c.5,000 ft (1,520 m) in the north, elevations reach over 10,000 ft (3,048 m) in the south. The

Sierra Madre del Sur (dĕl sr`) is a tumbled, broken mass of uptilted mountains that touch the Pacific coast but form into no clearly defined range. It spreads over S Mexico between the volcanic belt and the Isthmus of Tehuantepec and forms the natural harbor of Acapulco.

Sierra Madre

Principal mountain system, Mexico. It includes the ranges of the Sierra Madre Occidental (to the west), the Sierra Madre Oriental (to the east), and the Sierra Madre del Sur (to the south)—all running roughly northwest-southeast. The Sierra Madre Occidental extends for about 700 mi (1,100 km) parallel with the Gulf of California and the Pacific Ocean; summits reach elevations above 6,000 ft (1,800 m), with some exceeding 10,000 ft (3,000 m). The Sierra Madre Oriental originates near the Rio Grande to the north and extends roughly parallel with the Gulf of Mexico for about 700 mi; it has an average elevation of about 7,000 ft (2,150 m), but some peaks rise above 10,000 ft (Mount Peña Nevada). The Sierra Madre del Sur stretches through the southern Mexican states of Guerrero and Oaxaca, reaching elevations of about 6,500 ft (2,000 m), with a few peaks above 10,000 ft.