Trujillo Alto (Spanish pronunciation: [tɾuˈxiʝo ˈalto]) is a town and municipality of Puerto Rico.

Located on the northeastern coastal plain on the boundary between the Northern Karst Belt and Sierra de Luquillo, it is north of Caguas and Gurabo, southeast of San Juan, and west of Carolina.

Due to its proximity to the capital, San Juan, the city has become a suburb of the metropolitan area, which has sparked its growth during recent years.

The dam forms the Loíza Lake, a reservoir which serves as the main source of the water supply for San Juan, Puerto Rico.

During the 17th century, the Spanish crown granted Alonso Pizarro Hermona, from Trujillo in Spain, a vast ranch that covered the region.

Eventually, the inhabitants went to the Governor and asked for a permit to build a chapel, which was a requisite to officially found a town.

[11] The proximity of the city to the capital, San Juan, sparked significant growth and development in the region and during the 20th century, the population of Trujillo Alto increased dramatically.

[13] Hurricane Maria on September 20, 2017, triggered numerous landslides in Trujillo Alto, with its rain and winds.

Trujillo Alto's hydrographic system consists mainly of the Río Grande de Loíza, which crosses the municipality.

[18] There are also several creeks in the city: Colorada, Infierno, Limones, Naranjo, Grande, Pastrana, Haya Fría, and Maracuto.

[8] Also, Trujillo Alto is the site of Puerto Rico's main water reservoir: The Carraízo Dam, at the Loíza Lake.

The municipal buildings, central square and large Catholic church are located in a barrio referred to as "el pueblo".

Most of the barrios are spread through the rural section of the city, while the downtown area (Trujillo Alto Pueblo) is small, consisting only of eight primary streets.

The Bicentenary Walkway, located in the entrance to the city at the PR-181, features the remodeled historic steel bridge (one of the first permanent crossings of the Grande de Loiza River) as well as a gazebo.

Other places of interest are the Carmelitas de San José Convent, the Lourdes Grotto, and the Trujillo Alto Mountain Spring.

The economy of Trujillo Alto has relied mostly on agriculture, particularly sugarcane, coffee, tobacco, and minor fruits.

Trujillo Alto is the site of several factories of nutritional products, wood, metal, electrical machinery, and others.

The Fiestas Patronales de Santa Cruz is a religious and cultural celebration that generally features parades, games, artisans, amusement rides, regional food, and live entertainment.

In 2001, Trujillo Alto commemorated its bicentenary with the opening of a new park in the PR-181, which included a remodeling of the historical steel bridge.

In 2011, the Rubén Sánchez Montañez Court in Trujillo Alto, hosted the Cangrejeros de Santurce team of the Baloncesto Superior Nacional (BSN), which is the professional basketball league.

Despite the decline, in 2020 Trujillo Alto was the tenth largest municipality in Puerto Rico, in terms of population.

The first official mayor of Trujillo Alto was Juan Francisco Carazo, who was one of the residents that vouched for the founding of the town in 1801.

[60] The coat of arms features a shield with a blue border, with eight spurts of water representing the many springs, creeks, and rivers that flow in town.

Trujillo Alto is also known as the "City in the Country", for its proximity to the San Juan Metropolitan Area despite being mostly a mountain town.

In the past, communication with the town was limited because of its location on the other side of the Río Grande de Loíza.

In 1939, the United States Army built a steel bridge in the entrance to the town on the PR-181, to replace one of the older ones.

[6] The northern part of Trujillo Alto is serviced by the Puerto Rico Metropolitan Bus Authority, with various stops along the PR-181 and nearby neighborhoods.