The city is the birthplace of Juan Santamaría, the national hero of Costa Rica and the figure who gives the name to the country's main international airport, which is south of Alajuela downtown.

After increases of population in the five existing quarters then: Targuaz, Puás, Ciruelas, La Lajuela and Rio Grande, the citizens faced difficulties to maintain their religious obligations, so they requested permission to establish a parish and a public place of prayer from the Bishop of Nicaragua and Costa Rica, Monsignor don Esteban Lorenzo de Tristán.

Participation in important historical events by citizens of Alajuela has ensured the city's reputation as a storied place in Costa Rican history.

The national hero Juan Santamaría, who died during the Filibuster War in 1856 to remove invaders threatening Costa Rica's sovereignty, was born in Alajuela.

[11] The main exports of the region are coffee, sugar-cane, maize, beans, tobacco, citrus fruits, strawberries, tubers like cassava, flowers and ornamental plants.

More recently, Alajuela has seen important investment in free zone parks and heavy industry companies, with a considerable number of them dedicated to manufacturing a variety of medical devices.