Kalandra sector

The Kalandra sector was a sector located in Federation space.

In 2374, the Dominion launched a successful invasion of Betazed through the Kalandra sector. Considered by Starfleet Intelligence to be too far removed from the Dominion's main supply lines the invasion caught Starfleet by surprise. 

Starfleet Taskforce 59 launched an attack on a Jem'Hadar breeding centre near the Kalandra sector days before the Battle of Betazed. Their attack was beaten back due to heavier then expected forces in the system and reinforcements from surrounding areas. (: "Change in Command")

Operation Chestnut was designed to liberate Griffith II, a planet close to the Dominion's supply lines through the Kalandra sector. Once captured the world would be used as a staging ground to harass the Dominion's supply lines and weaken their position within the sector. (: "Always on My Mind")