The Islas Marías Federal Penal Colony is a penitentiary establishment of the Federal Government of Mexico, administered through the Federal Secretariat of Public Security. It is located on Isla María Madre, the northernmost and largest island in the Marías Islands archipelago.
Built in 1905, under the government of Porfirio Díaz, the prison of las Islas Marías was "the pride of the government" becoming the most modern prison model of its time, "escape proof", which operated as an alternative to house the delinquents, who due to their profile and background, could not be held in the prison of Lecumberri.
Until 1950 this prison colony was known as a feared detention center, due to violence, disease, and forced labor. It is calculated that the total number of prisoners to be housed there is above 29,000 .
During the government of Ernesto Zedillo the government decided to modernize the prison system and Islas Marias was deactivated. On 27 November 2003 it was declared a biosphere reserve but with the prison system still existing.
The prison situation in Mexico became so critical that the government announced in 2004 that they were reactivating the Islas Marias prison to transfer 2,500 prisoners from prisons all over the country.
The prison has had at least 76 escapes in the last 25 years of which 29 took place in 1986 alone. According to newspaper reports the causes are minimum vigilance, shortage of guards and equipment. Among the most dangerous to escape were criminals sentenced for drug trafficking, 28 murderers, and kidnappers. Of the 76 escapees from the Islas Marías only 10 have been recaptured. According to one source 95% of the escapes are due to corruption.
For many years the prison was administered by the Secretariat of the Interior. Over the years the prison population has fluctuated from 300 to 3000 prisoners.
In addition to prisoners, on Maria Madre island, there are employees of diverse institutions of the federal government, such as the Secretariat of Public Education, the Secretariat of the Environment, the Secretariat of Communications and Transport, Post Offices, and the Secretariat of the Navy.