Trujillo Alto is a municipality in Puerto Rico, located within the San Juan metropolitan area and bordering the capital city of San Juan to the north and the municipality of Carolina to the east. With a population of roughly 74,000, it is one of the most populated municipalities on the island, having grown steadily through the 20th century as the San Juan area expanded outward into the surrounding hills. The municipality was founded on January 8, 1801, and named for Alonso de Trujillo, a Spanish settler. For much of its early history it was an agricultural community, but its proximity to San Juan gradually transformed it into a residential suburb, a role it continues to play today as part of the island's largest metropolitan region. Trujillo Alto's defining natural feature is the Río Grande de Loíza, one of Puerto Rico's most significant rivers, which flows through the municipality. In 1953 and 1954, the Carraízo Dam was built on the river in the barrio of Carraízo, forming Loíza Lake, also known as Carraízo Lake. The reservoir serves as the principal source of water for the San Juan metropolitan area and provides a scenic and recreational centerpiece for the municipality, with boating, fishing, and riverside activities. The municipality is affectionately known as "el Pueblo de los Arrecostaos," or the laid-back town, a nickname that captures its relaxed character relative to the capital. Its location also places it near the Ruta del Lechón, Puerto Rico's famous roast-pork culinary route, tying Trujillo Alto into one of the island's most beloved food traditions. Public education is provided by the Puerto Rico Department of Education, which operates elementary, middle, and high schools across the municipality. Transportation is anchored by the Metropolitan Bus Authority's network, which serves Trujillo Alto as part of the San Juan metro's fixed-route system, while major roadways connect the municipality directly to San Juan, Carolina, and the broader eastern corridor of the island.