Elba II asylum
The Elba II colony was a Federation asylum for the criminally insane, operating in the latter half of the 23rd century on the planet Elba II. 

The facility was set aside for the purpose of isolating and offering what treatment was available to a handful of beings diagnosed with an incorrigible criminal insanity. Governor Donald Cory oversaw 15 patients who met that description in the late 2260s, including Elba II's most notorious resident, former Starfleet Fleet Captain Garth of Izar. 

With dangerous patients, Elba II had appropriately extensive security precautions. Patient living quarters were protected by individual force fields, and the colony dome itself was protected by a field that, when in place, prevented beaming and a could even withstand a phaser barrage from a  starship in orbit. The field was said to the weakest on "the far side of the planet" while the dome itself could not be breached by anything the crew of the Enterprise had at their disposal save for the ship's own weaponry. The toxic gases of Elba II's atmosphere provided a final daunting barrier. 

None of the security measures precluded patients from attempting escape, as Garth tried in 2269. The mad, shapeshifting former officer ran circles around Gov. Cory and for a time, had the complete run of the facility, but never the means to get out. Even after the capture of Captain James T. Kirk and Commander Spock, with the  orbiting above, Garth and his followers never got closer to freedom than the steps they took from their cells.

A revolutionary new medicine, delivered by the Enterprise in her visit of 2269, promised to almost immediately reverse arterial and brain damage and was hoped to aid the rehabilitation of the wards of Elba II. ()

The Tantalus Penal Colony held prisoners who were deemed curable. ()

Residents of the Elba II asylum

Staff 
 Governor Donald Cory

Patients 
 Garth of Izar
 Marta
 Andorian
 Six Humans
 Tellarite

Races on the planet 
Andorian
Human
Orion
Tellarite
Prisons and penal colonies
Medical organizations