"Only Qo'noS endures".
- Main article: Klingon history
Qo'noS had achieved interstellar travel capability around the time of Kahless in the 9th century. Warp capability was achieved some time after 1947 and warp 6 had been achieved some time before 2152. (TNG: "Rightful Heir"; DS9: "Little Green Men"; VOY: "Day of Honor"; ENT: "Judgment")
In 2293, the Klingon moon of Praxis, a key energy-production facility for the Klingon Empire, exploded after an accident involving over-mining which sent out a subspace shock wave, causing severe damage to the planet's ozone layer. This event forced planning for the evacuation of the planet and led to the signing of the First Khitomer Accord with the Federation. (Star Trek VI: The Undiscovered Country)
- Caves of No'Mat
- Hamar Mountains
- Sea of Gatan
- Kang's Summit
- Kri'stak volcano
- Lake of Lusor
- Skral River
- Glob fly
- Grint hound
- Grishnar cat
- Jackal mastiff
- Monster dog
- Kolar beast
- Saber bear
- Serpent worm
Background information Edit
|Warning! This section may contain spoilers for new Star Trek material.|
For the planet's appearance in Star Trek Into Darkness, production designer Scott Chambliss took classical influence for its look. "The quadrant of the city where the action takes place is sort of an interpretation of the Roman Colosseum, the warrens below the Colosseum floor," he said. 
The name of the homeworldEdit
The Klingon homeworld remained canonically unnamed until Star Trek VI: The Undiscovered Country, in which it was identified as "Kronos", spelled that way in the film's script.  The spelling "Kronos" was also used in most of the scripts of Star Trek: Deep Space Nine episodes.  It was also used in the script of the Star Trek: Enterprise episode "Broken Bow".  According to the pronunciation guide in the script of DS9: "Tears of the Prophets", KRO-nos is the phonetic spelling of "Kronos". 
"Chronos" was a more rare alternative spelling used in the scripts of only two Star Trek: Deep Space Nine episodes, "Once More Unto the Breach"  and "Extreme Measures"  The spelling "Kronos" was however identified as the correct one, when it was seen on screen in Star Trek Into Darkness.
An alternate name for the Klingon homeworld has also been used. "Kling" was first mentioned on screen in TNG: "Heart of Glory" and depicted as a location on "The Explored Galaxy" star chart. According to the Star Trek Encyclopedia, at the time "Heart of Glory" was written, "Kling" was in fact intended as the name of the Klingon homeworld, but once the episode was filmed, it was realized that the name sounded pretty silly. "Kling" was therefore referenced in the Encyclopedia as a district or a city on the Klingon homeworld.
Reference works, that predate Star Trek VI: The Undiscovered Country have offered several other names. According to the Starfleet Medical Reference Manual, the Klingon homeworld was the planet "Klingonii" also known as "Epsilon Sagittarii B". Star Trek Maps (Chart B), named the homeworld as "Kazh" and the star it orbited as "Klingon". In The Worlds of the Federation (pgs. 114, 154), the homeworld was called both "Klinzhai" and "Kling". "Kling" and "Klinzhai" have also been used in the FASA RPG and various novels, as well as in the Star Trek: Starfleet Command video game series.
According to the Star Trek Encyclopedia and The Klingon Dictionary by Marc Okrand, "Kronos" is the pronunciation and anglicanized form of the Klingonese word "Qo'noS". According to the script of "Tears of the Prophets" however, where the Klingon death chant is spelled in Klingonese: "neH taH Kronos. Hegh bat'lhqu Hoch nej maH. neH taH Kronos. yay je bat'lh manob Hegh." "Kronos" is the way the name is spelled in Klingonese as well. 
According to Star Trek: Star Charts (p. 56), "Kronos", "Kling" and "Qo'noS" are all alternative names for the homeworld.
Location of Qo'noSEdit
On screen and in dialogue, the Klingons have been exclusively identified as an Alpha Quadrant race. The association with the Alpha Quadrant began to be established in Star Trek: The Next Generation. In "A Matter Of Honor", the Klingons and the Romulans were mentioned to have had a series of skirmishes along their border. In "Reunion", K'Ehleyr stated that Klingon wars were rarely confined to the Empire. These wars had a tendency to spread to the neighboring star systems, like the Tholians and the Ferengi. All three were later on established to be Alpha Quadrant powers, in such episodes as DS9: "The Search, Part II", "Call to Arms" and VOY: "Q2". The position of Ferenginar only a few sectors away from Cardassia was established on a star chart in DS9: "When It Rains...".
Star Trek: Deep Space Nine confirmed what had been already stated and added onto it. In "The Die is Cast", the Dominion identified the Klingons as a threat originating from the Alpha Quadrant. "The Way of the Warrior" was the first episode that implied that the Klingons and the Cardassians shared a border. The Klingon Empire launched an attack against the Cardassian Union for the best interest of the Alpha Quadrant. It was revealed in this episode that relations between the two great powers have been for the most part amicable, save for the Betreka Nebula Incident that began an eighteen-year-long conflict between the two powers. In "Blaze of Glory", Captain Benjamin Sisko and Martok were discussing the ramifications of Human terrorists killing millions of Cardassian citizens. They agreed that the Cardassian allies, the Dominion, would retaliate not only against the Federation, but against the Klingons and the entire Alpha Quadrant. In "In the Pale Moonlight", Sisko attempted to persuade the Romulan Senator Vreenak to consider having the Romulans join the offensive against the Dominion. According to Sisko, if Cardassia, the Klingon Empire and the Federation were all conquered by the Dominion, the Romulans would find their territory surrounded by a single enemy. In the "Tears of the Prophets", Sisko stated that the three great powers, the Humans, the Klingons, and the Romulans have one goal: to drive the Dominion out of the Alpha Quadrant. In "When It Rains...", Chancellor Gowron envisioned the Klingon Empire as the saviors of the Alpha Quadrant if they could drive the Dominion out of the quadrant.
The association of Qo'noS and the Alpha Quadrant was carried over to Star Trek: Voyager as well. In "Faces", Chief Engineer B'Elanna Torres boasted that Klingon females were renowned in the Alpha Quadrant for their physical prowess and voracious sexual appetites. In "Flashback", Captain Kathryn Janeway reminisced about what it would be like to live in Captain James T. Kirk's era, with the Alpha Quadrant still largely unexplored and Humans on the verge of war with the Klingons. In "Flesh and Blood", Chakotay identified the Klingon bat'leth as an Alpha Quadrant weapon.
The close proximity of Qo'noS and Earth was established in the pilot episode "Broken Bow" of Star Trek: Enterprise. Qo'noS was located only four days away at warp 4.5. "Two Days and Two Nights" established that this was at most only 90 light years away, as that was the farthest away from Earth any Human had ever gone up to that point.
Reference works that predate Star Trek: The Next Generation depict the location of the Klingon Empire and their homeworld in what has been established as the Alpha Quadrant. These include such works as the Star Trek Star Fleet Technical Manual (T0:02:07:00) and Star Trek Maps (Chart A). More recent reference works have however moved the Klingon Empire into the Beta Quadrant. They show that the Empire borders only the Romulan Star Empire and the United Federation of Planets. Despite the conflicting canonical references establishing the Ferengi and the Cardassians as neighbours of the Empire, they are depicted on the other side of the Federation, away from the Klingons in these graphics. Only one of these graphics depicting the Klingons in the Beta Quadrant made an illegible brief on screen appearance as a display graphic on a PADD in Star Trek: Insurrection.  
Star Trek: Star ChartsEdit
The capital city for the uniglobal government and for the Klingon Empire was the First City on Qo'noS. The dominant species on the planet were the Klingons. Points on interest on this world were the Great Hall, Qam-Chee, Tong Vey, Quin'lat, Temple of G'boj, Kri'stak volcano, Lake of Lusor, and Caves of Kahless. The Klingons were warp capable in 930 A.D. The planet was on the front line during the brief Klingon Civil War of 2368. In 2378, there were 3.84 billion Klingons living on the planet. The planet Qo'noS (Kronos, Kling) was located in the Qo'noS system. The star system was located in the Qo'noS Sector, adjacent to the Archanis Sector. The star Qo'noS was a K-class star with a magnitude of +3, which was ten times brighter than Sol. In 2293, the USS Enterprise-A visited this system when escorting Kronos One to Earth. (pg. 55, 56, 61, 62)