The Typhon Sector is located in Federation space, not far from the Romulan Star Empire in the Beta Quadrant. Much of the sector is encompassed by the Typhon Expanse, of which very little of has been explored. As of 2386, there were three named star systems which had been surveyed. One of these is the Azandria System, home to a Class M planet of the same name and Leto Colony. Because of the Expanse's quirky time distortions, travel through the sector can be hazardous. Deep Space 4 is also located within the sector.
In 2373, the sector was the location of the initial engagement between Vice Admiral Jeremiah Hayes' Starfleet task force and a Borg cube en route to Earth. The fleet was unable to stop the cube at Typhon and pursued the cube all the way to Sector 001. (ST: First Contact)