(covers information from several alternate timelines)
A sanctuary or safe haven was a safe location where people or animals found shelter. They might be religious in nature, where they were additionally known as a retreat.
According to Chris Brynner, the Sanctuary Districts in the United States of America in the 21st century were created to give people in trouble food and a place to stay. (DS9: "Past Tense, Part I")
In 2135, T'Pol, working as an agent for the Vulcan Ministry of Security, killed another undercover agent, Jossen. She took refugee at the sanctuary of P'Jem and struggled with this situation for months before she underwent the fullara ceremony. (ENT: "The Seventh")
The monastery at P'Jem, a remote sanctuary until 2151
During a further visit at the monastery at P'Jem, T'Pol described the place as an ancient spiritual retreat, a remote sanctuary for kolinahr and peaceful meditation. (ENT: "The Andorian Incident") Following its destruction by the Andorian Imperial Guard, Ambassador Soval called it one of Vulcan's most revered sanctuaries. (ENT: "Shadows of P'Jem") T'Pol later called the act using a sacred sanctuary to spy on others a dishonorable practice. (ENT: "Shockwave, Part II") The T'Karath Sanctuary was also a sacred Vulcan place. (ENT: "The Forge", "Awakening", "Kir'Shara")
The T'Karath Sanctuary
When Captain Maximilian Forrest was reviewing reports in his quarters aboard ISS Enterprise, his mistress Hoshi Sato asked him what he was doing and that he should see his quarters as his sanctuary, a place to get away from status reports. (ENT: "In a Mirror, Darkly")
If a Starfleet vessel were to come across an endangered species, protocol required the transport of the creature to a xenologic facility or sanctuary. (DIS: "Magic to Make the Sanest Man Go Mad")
In 2268, Lokai requested political asylum aboard the USS Enterprise which he called a "sanctuary". (TOS: "Let That Be Your Last Battlefield")
During he talked with Kevin and Rishon Uxbridge, Captain Jean-Luc Picard asked the Uxbridge wife why their house was safe, why it was a sanctuary. (TNG: "The Survivors")
In a holographic recreation of the events that led to the murder of Doctor Nel Apgar, Manua Apgar called her private rooms aboard the Tanuga IV research station her sanctuary. (TNG: "A Matter of Perspective")
In 2370, Kang learned about the location of the Albino's sanctuary through an amulet sent to him by one of the Albino's wives. (DS9: "Blood Oath")
The Nechisti shrines on the Nechani homeworld were considered sanctuaries. (VOY: "Sacred Ground")
Unimatrix Zero, a virtual sanctuary
Charlene, wife of Kenneth in the holographic program Doctor's Family Program Beta-Rho stated, that she wanted their home to be a sanctuary, the place he can come and have all the cares of the day disappear. (VOY: "Real Life")
Sojef called the Ba'ku village on their planet a "sanctuary of life" and asked the away team from the USS Enterprise-E to disarm themselves. (Star Trek: Insurrection)
The con artists Dala and Mobar spoke of their sanctuary while acting as monks during a meeting with Neelix in 2376. (VOY: "Live Fast and Prosper")
Unimatrix Zero was the virtual sanctuary of members of the Borg resistance movement. (VOY: "Unimatrix Zero", "Unimatrix Zero, Part II")
By 3188, Sanctuary Four was a place where trance worms could be taken to protect them from going extinct. (DIS: "That Hope Is You, Part 1")