Question: Where were the Aztecs located?
Context: The geography of Mesoamerica describes the geographic features of Mesoamerica, a culture area in the Americas inhabited by complex indigenous pre-Columbian cultures exhibiting a suite of shared and common cultural characteristics.  Several well-known Mesoamerican cultures include the Olmec, Teotihuacan, the Maya, the Aztec and the Purépecha.  Mesoamerica is often subdivided in a number of ways.  One common method, albeit a broad and general classification, is to distinguish between the highlands and lowlands.  Another way is to subdivide the region into sub-areas that generally correlate to either culture areas or specific physiographic regions. Tapachula de Córdova y Ordóñez, simply known as Tapachula, is a city and municipality located in the far southwest of the state of Chiapas in Mexico, near the Guatemalan border and the Pacific Ocean.  It is one of the most important cities of Chiapas economically as the capital of the agriculturally rich Soconusco region as well as port for trade between Mexico and Central America.  The area was originally inhabited by the Mames as a region under the control of the Mame state of Xelaju but was first established as a city by the Aztecs in the 13th century.  Most of its economic importance has come since the late 19th century with the establishment of coffee plantations.  This agricultural production began a history of migration into the area which continues to this day and has left the city with a significant Asian and German cultural presence as well as large Mayan and Nahua indigenous populations. Pasaco (] ) is a municipality in the Jutiapa department of Guatemala, located near the Pacific Ocean on the Border with El Salvador.  It was originally formed when a group of Aztecs broke off at the arrival of Hernán Cortés, and went further south into what is now Guatemala (then Coahtemalan, or The Land of Abundance, in a Mayan dialect).  They united with some groups of Indians, pushing others into what is now El Salvador, recognizing Cortés as a villain, not Quetzalcoatl, or the great white God returned, as the Náhuatl, or Aztec leadership supposed at that time. Coixcas describes a pre-conquest community, and its inhabitants, located between the modern Mexican towns of Tixtla and Apango.  The Coixcas people resisted and repulsed attempts by the Aztecs to conquer their community.  The area was later captured by the Spanish conquistadores. Viejas Arena at Aztec Bowl (formerly named Cox Arena), located on the San Diego State University (SDSU) campus in San Diego, California, is the home of the San Diego State Aztecs men's basketball and women's basketball teams.  Viejas Arena opened its doors to the campus and community in July 1997 and seats 12,414 for basketball and up to 12,845 for concerts.  The facility also hosts SDSU's commencement ceremonies.  Previously, the Aztecs played at Peterson Gymnasium also on the SDSU campus.  However, the men's basketball team played most of their home games at the San Diego Sports Arena prior to Viejas Arena's construction. The Mezquital Valley (Otomi: B’ot’ähi) is a series of small valleys and flat areas located in Central Mexico, about 60 km north of Mexico City, located in the western part of the state of Hidalgo.  It is part of the central Mexican highlands, with altitudes between 1,700 m and 2,100 m above sea level.  It is one of Mexico's main semi-arid/area regions, whose native vegetation is dominated by cactus species, mesquite trees, and maguey with pine and oak trees in the highest elevations.  It is considered to be part of the northern extension of Mesoamerica, with one major archeological site, Tula, which was the main city of the Toltecs, an important influence for the later Aztecs, this area was on two important Aztec tribute regions, Teotlalpan and Jilotepec Province.  However, from the Aztec period to the 20th century, it was sparsely populated and very poor, with one main indigenous ethnicity, the Otomis.  In the 20th century, irrigation works were created to take advantage of the water in the Tula River, along with wastewater drained from the Valley of Mexico for agriculture.  Today the valley produces various grains and produce, including one-quarter of all green chili peppers grown in Mexico. Chapultepec Castle (Spanish: "Castillo de Chapultepec" ) is located on top of Chapultepec Hill.  The name "Chapultepec" stems from the Nahuatl word "chapoltepēc" which means "at the grasshopper's hill".  It is located in the middle of Chapultepec Park in Mexico City at a height of 2,325 meters (7,628 ft) above sea level.  The site of the hill was a sacred place for Aztecs, and the buildings atop it have served several purposes during its history, including that of Military Academy, Imperial residence, Presidential home, observatory, and presently, the National Museum of History. The San Diego State Aztecs men's basketball team is the college basketball program that represents San Diego State University, located in San Diego, California.  The school's team currently competes in the Mountain West Conference, and play their home games in Viejas Arena.  The team began play in 1921 and have been to 6 NAIA tournaments winning in 1941, 3 NCAA Division II tournaments, 5 NIT tournaments, and 11 NCAA Division I tournaments.  Since joining the Mountain West Conference, the Aztecs have won 4 MWC tournaments.  Former players who went on to achieve notable success in other areas are Art Linkletter and Tony Gwynn. Teotihuacan , also written Teotihuacán (] ,    ), is an ancient Mesoamerican city located in a sub-valley of the Valley of Mexico, located in the State of Mexico 40 km northeast of modern-day Mexico City, known today as the site of many of the most architecturally significant Mesoamerican pyramids built in the pre-Columbian Americas. Qualcomm Stadium is a San Diego Trolley stop on the Green Line.  The elevated station has an island platform as well as side platforms.  It is located in the parking lot of the SDCCU Stadium, home to the San Diego State Aztecs football team, and is frequently used during major stadium event days.  Outside of events, the large parking facilities also make for a massive park and ride facility for travelers from northern portions of the city and county.
Answer: a sub-valley of the Valley of Mexico