The Escuela Nacional Preparatoria (English: "National Preparatory School") opened its doors on February 1, 1868. It was founded by M.D. Gabino Barreda folowing orders of the then President of Mexico Benito Juárez. It is the oldest institution of the modern UNAM.
This institution location was the Antiguo Colegio de San Ildefonso (English: "San Ildefonso College"), which is at the heart of Mexico City, Historic Center. At that time, education length at that level was of 5 years.
Following this, because of the increasing demand, nine more schools were built, as well as a new organizational organism called General Direction. These schools where located at the center of Mexico City, but due the increasing size of the city and the necessity for modern buildings, they where relocated in the vicinity of the city, mainly orientated in the southern neighborhoods like Coyoacán, Xochimilco and Villa Coapa.
Its actual director is Luis Samuel Saloma, who yearly runs a tour along the 9 schools of the ENP, giving a final concert at the Auditorium at the General Direction.
"City High School" at Oklahoma has an exchange of 15 days with the School number 9.
Although the schools all have a name and a number, in the daily talk, they are referd rather by the numbers than by the names.
The school has mainly 2 kinds of study plan: