Tlalpan (Classical Nahuatl: Tlālpan [ˈtɬaːlpan̥] ^ⓘ, 'place on the earth') is a borough (demarcación territorial) in Mexico City. It is the largest borough, with over 80% under conservation as forest and other ecologically sensitive area. The rest, almost all of it on the northern edge, has been urban since the mid-20th century. When it was created in 1928, it was named after the most important settlement of the area, Tlalpan, which is referred to as “Tlalpan center” (Tlalpan centro) to distinguish it from the borough.

This center, despite being in the urbanized zone, still retains much of its provincial atmosphere with colonial era mansions and cobblestone streets. Much of the borough's importance stems from its forested conservation areas, as it functions to provide oxygen to the Valley of Mexico and serves for aquifer recharge. Seventy per cent of Mexico City's water comes from wells in this borough.

However, the area is under pressure as its mountainous isolated location has attracted illegal loggers, drug traffickers, and kidnappers; the most serious problem is illegal building of homes and communities on conservation land, mostly by very poor people. As of 2010^[update], the government recognizes the existence of 191 of the settlements, which cause severe ecological damage with the disappearance of trees, advance of urban sprawl, and in some areas, the digging of septic pits. The borough is home to one of the oldest Mesoamerican sites in the valley, Cuicuilco, as well as several major parks and ecological reserves. It is also home to a number of semi-independent “pueblos” that have limited self-rule rights under a legal provision known as “usos y costumbres” (lit. uses and customs).

What is now called "Tlalpan center" or sometimes "the historic center of Tlalpan" began as a pre-Hispanic village located at the intersection of a number of roads that connected Tenochtitlan (Mexico City) with points south. This village was renamed Villa de San Agustín de las Cuevas in 1645, with the last part “de las Cuevas” referring to the many small caves in the area. During the colonial period, the village was a modest farming village, known for its fruit orchards. However, the forests of the area made it attractive to the elite of Mexico City who built country homes and haciendas here, much as they did in other areas south of the city such as Chimalistac, San Ángel and Coyoacán.

Many of these homes and manor houses of the former haciendas still remain in and round Tlalpan center. As the urban sprawl of Mexico City only began to reach this area starting in the mid-twentieth century, much of the former village has retained its provincial streets, older homes and other buildings with façades of reds, whites, blues and other colors, although a number have been converted into other uses such as cafes, restaurants and museums. This makes the area similar to neighboring Coyoacán, and like this neighbor, Tlalpan center is popular with visitors, especially on weekends as people come to see its provincial main square/garden, mansions, narrow winding cobblestone streets lined with large trees, eat in its restaurants and cafes and visit its many nearby parks and other green areas. One popular area with cafes and restaurants is La Portada, on one side of the main plaza.

Tlalpan center has eighty structures from the 16th to the 20th centuries that have been classified by INAH as having historic value. Some of these include old Tlalpan Hacienda, the former home of the Marquis de Vivanco and the San Agustin parish church. The borough of Tlalpan has sought World Heritage Site status for the area because of these structures, the area's history and the nearby site of Cuicuilco.

The center of this former village is the main square or garden officially called the “Plaza de la Constitución” but better known as the “Jardín Principal” (Main Garden). Visually, what stands out is the large kiosk in the center, but historically more important is the “Arbol de los colgaldos” (Tree of the Hanged). This tree, still alive, was used to hang political enemies and bandits, including those opposed to the invading French Army during the French Intervention in Mexico. On weekends, vendors set up stalls selling handcrafts and other items. To one side of the plaza, there is a cantina called La Jalisciense, one of the oldest in Mexico City, having been in operation for over 135 years.

Facing the Jardín Principal, there is the “Palacio de Gobierno” (Government Palace), which was the site of the government of the State of Mexico, when Tlalpan served as state capital for six years in the early 19th century. Since then, it was used as a barracks for Benito Juárez’s soldiers, a jail, a residence for the Empress Carlota and the site of the Instituto Literario (today the Universidad Autónoma del Estado de México) . Today, it serves as the headquarters of the borough, although it is also commonly referred to as the “ex palacio municipal” (former municipal palace) referring to the time when Tlalpan was an independent municipality in the State of Mexico. The current structure was built between 1889 and 1900 in Neoclassical style.