Klingon space
Klingon space or Klingon territory was the territorial region of space claimed by the Klingon Empire.

Qo'noS and many other Klingon systems, including Ty'Gokor which was said to lie deep within Klingon territory, were located in the Beta Quadrant. ( display graphic;  display graphic; )

Expansion 
The Empire contained Klingon colonies as well as annexed, previously inhabited worlds. (e.g., ; ) The foundation of a Klingon colony could be preceded by bio-surveying potentially suitable planets. () For conquered inhabited worlds, the traditional Klingon practice called for the execution of all government officials, and the installation of an Imperial Overseer, e.g., a governor, to put down any further resistance. An alternative approach was the creation of a puppet regime under a native governor. (; ) 

The planet Krios was a Klingon colony on the border of Federation space. In 2367, the Kriosians sought independence from the Empire. According to Klingon Ambassador , "There was a time when the Empire would crush a rebellion. Now it is tolerated. We have enough problems on the home planet. We don't wish to divert resources to such a trivial war." When asked if the Empire considered granting them independence, Kell responded, "Perhaps. We'll conquer them again later, if we wish." ()

Noted incursion 
Klingons were a very territorial species, vigorously patrolling the borders of their Empire with severe consequences for any trespassers. The Klingon Empire shared borders with the Romulan Star Empire and the Federation, the latter of which was protected by a neutral zone during the later 23rd century. (e.g. ; ; ; )

In 2016, a Vulcan ship crossed into Klingon space near H'atoria and was immediately destroyed by the Klingons. ()

In 2152, the  tracked a refugee ship from the Klingon protectorate of Raatooras to a system just outside of Klingon territory, where they discovered that it had been rescued by the Human vessel . Following an engagement between the two vessels, Enterprise Captain Jonathan Archer was put on trial on Narendra III, under the suspicion of conspiring against the Klingon Empire. While awaiting sentence, Archer was relying on Sub-commander T'Pol and Commander Charles Tucker III to get Enterprise safely out of Klingon territory whatever the outcome. Archer was sentenced to lifelong exile on Rura Penthe. As Enterprise was deep inside Klingon territory, T'Pol noted that an attempt to rescue the Captain was out of the question. However, she was able to recover Archer using diplomatic channels. ()

The Tezra, a ship of the Tellarite Mining Consortium, was seized by the Klingons after Captain Skalaar crossed into Klingon territory while hauling firesalt. As Skalaar recalled, he hoped to trim two or three days off his journey by cutting across the most insignificant corner of Klingon space, only to learn very quickly that there was no thing as an insignificant corner of Klingon space. To pay his impound fee, Skalaar become a bounty hunter. In  2153, he captured Jonathan Archer, intending to deliver him to the Klingons. Following Archer's abduction, Enterprise learnt from Kago that he was halfway through Klingon space. Less than six light years from Klingon space, Enterprise set a course to search and ultimately recovered their captain. ()

In May of 2154, a group of Augments crossed into Klingon space aboard a highjacked Bird-of-Prey. Arik Soong suggested the Briar Patch as a hiding place once they were safely through Klingon space but his suggestion was rejected by Malik, the self-appointed leader of the Augments. Later, Enterprise used a Klingon warp signature and a universal translator programmed with seven Klingon language dialects to pass as a Klingon vessel within Klingon territory to intercept the Augments. ()

Later that year, Enterprise set course for Klingon territory after Doctor Phlox was abducted. Captain Archer requested the assistance of  in their search, noting in his starlog "We'll have a better chance of making it through Klingon territory with twice the firepower." ()

In 2233 of the alternate reality, the  was on the edge of Klingon space when it was attacked by the Narada, a Romulan vessel from 2387 of the prime timeline. ()

In 2256, during the Battle of the Binary Stars, T'Kuvma broadcast a message from his flagship on all subspace bands: "Members of the Federation. What you call your most remote borders, I call too close to Klingon territory." ()

Six months after the start of the , the  was running drills near Klingon space. It was later responsible for scuttling the , a sister ship which was adrift by Klingon territory. ()

When Captain  was abducted in a shuttlecraft by a  vessel, Acting captain Saru ordered Commander Airiam to inform Lieutenant Paul Stamets that Discovery may be making multiple spore jumps in rapid succession throughout Klingon space in an attempt to track Lorca's captors. Repeated use of the spore drive in attempts to rescue Lorca resulted in Ripper entering an extreme state of cryptobiosis and becoming unresponsive. Stamets resorted to injecting himself with a sample of  DNA and entering the spore chamber to act as the navigation computer. The jump was a success and Lorca was recovered, along with another Starfleet prisoner, Lieutenant , with Discovery departing Klingon space. ()

In 2259,  took refuge in the Ketha Province on Qo'noS, knowing that for Starfleet to approach Klingon space would risk a war. After using a K'normian trading ship to recover Khan from Qo'noS against the orders of Admiral Alexander Marcus, Captain  found that a warp core malfunction had stranded his ship on the edge of Klingon space. As it transpired, Marcus had the Enterprise warp core sabotaged, intending for the Enterprise to use advanced long-range torpedos against Khan on Qo'noS. The plan was for the Klingons to discover the Enterprise and in response to the torpedo attack, start a war with the Federation. Thankfully,  was able to repair the warp drive, allowing the Enterprise to return to Federation space. ()

In 2293, the  entered Klingon space, masquerading as the freighter Ursva, to rescue Captain James T. Kirk and Doctor Leonard McCoy from Rura Penthe. Meanwhile, Captain Hikaru Sulu ordered the  on an aborted raid into Klingon territory from Sector 21185 on an ill-advised rescue attempt. Sulu, who attempted to sneak the Excelsior into Klingon territory by traversing the Azure Nebula at maximum warp, was discovered by a Klingon battle cruiser commanded by Kang. While Sulu explained that the Excelsior was on a survey mission, studying the nebula, and had gotten lost due to a malfunction in the navigation system, Kang offered to escort the Excelsior back to Federation space. As the Excelsior emerged, she fired a modulated positron beam that triggered a thermochemical reaction, and successfully disabled Kang's ship. The Excelsior then made a break for Qo'noS, but was almost immediately intercepted by three Klingon battle cruisers. The Excelsior and Klingon ships continued to exchange fire until the Excelsior was forced to retreat back to Federation space. (; )

Following the outbreak of civil war in the Empire in late 2367, Captain Jean-Luc Picard of the  led a Federation fleet into Klingon territory in order to prevent Romulan forces from covertly supplying the House of Duras. Though Commander Sela noted that Romulan vessels could slip through Klingon territory at will via cloak, Picard employed a tachyon detection grid to detect them. ()

In 2369, the Enterprise found Relay Station 47 abandoned, with evidence suggesting that encrypted messages sent from there had been tampered with. As the station was close to Klingon space, the Klingons came under suspicion in connection to the disappearance of the crew. The lone survivor, Aquiel Uhnari, took the station's shuttlecraft Verne, which was later found by Klingon patrol ship on the Klingon side of the border, on a course for Sector 2520. According to Governor , who was in charge of that regions, "[s]he [was] lucky my patrol ship did not destroy her vessel on sight." ()

In 2372, during the Klingon-Cardassian War, the Pentath system bordered Klingon territory. When an outbreak of Rudellian plague struck the Cardassian colony on Pentath III, the Cardassians feared raids and so requested protection from Starfleet for their convoys of medical supplies and relief workers. ()

In 2373, a memory virus that Lieutenant Commander Tuvok had contracted aboard the Excelsior eighty years earlier led him to advise extreme caution when close to Klingon space. Now aboard the , Tuvok was reminded by  B'Elanna Torres that the Klingon Empire was on the other side of the galaxy. ()

During the , Starfleet sent an infiltration team to Klingon territory in order to prove that Klingon Chancellor Gowron was a shapeshifter. This team consisted of Captain Benjamin Sisko, Lieutenant Commander Worf, Constable Odo and Chief Miles O'Brien. Their mission was complicated when they learnt from Starfleet Intelligence that Gowron had relocated Klingon military headquarters to Ty'Gokor. Located in an asteroid field deep in Klingon space, Ty'Gokor was considered the heavily fortified installation in the Empire. ()

In an unknown, future timeframe, the  crossed the border into Klingon territory to scan the Devron system for a temporal anomaly. ()

See also 
 Klingon planets
 Klingon-Romulan border
 Federation-Klingon border

Qo'noS
Regions