Until today, the exact origin of the name of Tijuana is unknown.
The word Tijuana, as known today, began to be used in documents from the mid 19th century.
Among the first documents where the word Tijuana as we know it was used, are birth and marriage certificates, such as "Jose Upton and Ma. Luisa Robles, married in Tijuana ranch January 21st, 1870, at the home of Ignacio Argüello. He, 42 years old, native of London, England, carpenter, resident of this city, legitimate son of Jose Upton and Anna Gremham, both from England. Her, 30 years old, widow, legitimate daughter of Alejandro Roles and Guadalupe Armenta, the first an England native and the second of this municipality. "(Source: Paul L. Martinez, Guia Familiar de Baja California)