Aserrí is a canton of Costa Rica located in the center of the province of San José, on the intervolcanic plateau of the Central Valley, and partially belonging to the Great Metropolitan Area.
Canton of Aserrí has an area of 167.10 km² and an average altitude of 1.308 masl. The highest point of the canton is the hill Caraigres, which is located in the north of the district of Legua, and near the border with the canton of Acosta, and is part of the Cerros de Escazú, a mountain range that crosses several cantons of the center and west of the province of San José. It has an elevation of 2 506 masl., approximately.