The city of Gadrin, along with its twin city Hedrett, was the only major non-Tarasin settlement on the surface of Cularin. The other non-native cities were built on platforms which towered over the jungle.
Scout Reidi Artom helped found Gadrin, the first alien towns in Cularin, on the west bank of the Estauril River, near the location of the Hiironi irstat. Artom had met with the Hiironi and they helped her to build the first buildings, made out of native woods, where the Estauril flowed to the base of the Cloud Mountains.
Urban planning for Gadrin was supposed to use a grid, but the quick growth of the city and the incoming population made it impossible. The spaceport was built to the other side of the river, where there was nothing. Later settlements in that side of the Estauril would become a second town, Hedrett.
After Hedrett was founded on the opposite side of the river, Artom built a great bridge to connect them. Further expansions of the cities, some of them using prefab buildings imported from other planets, reached the jungle. This led the native Tarasins to oppose to new buildings, and eventually to the Tarasin Revolt. The Revolt ended with a treaty, the Cularin Compact, recognizing the Tarasins's rights and the obligations of the aliens to respect the local ecology. Military equipment that the Tarasins had left after the war, was re-sold in Gadrin and off-planet.
To avoid further expansions to the jungle, further cities in Cularin would not be built on the surface, but over it: The platform cities could expand without affecting the jungle. The building of the platform cities reduced the importance of Gadrin and Hedrett, and their populations declined. Despite this, the "twin city" was sometimes viewed as the unofficial capital of Cularin.
As Artom used her wealth and fame to improve the development of Cularin and to transform it in an advanced planet comparable to the Core, she was well-loved in Gadrin, Hedrett and the platform cities. One of the more notable locations in Gadrin, as the first Cularin city ever, was a museum built for Reidi Artom in Gadrin. The museum had holovids, personal effects, and logbooks of the explorer, along with other displays. A twenty meter tall statue of Artom stood in front of the museum. A road led from Gadrin to the Hiironi irstat. A silver archway stretched above the start of that road.
Though the other people of the Cularin system tended to see Gadrin and Hedrett as one city, the two towns had their own distinctive flavors, architecturally and politically - and in fact were rivals in many senses. At some point, for instance, Hedrett annexed the spaceport that Gadrin had built in what was by then Hedrett soil. Gadrin considered the creation of a new spaceport but, as Hedrett's was comfortably near, the population showed no interest in that.
Gadrin had the more rambling layout of the two. Most Gadrin buildings were wooden, though there were some prefabs brought in as well. Gadrin didn't have a spaceport, its original one having been corrupted by Hedrett. Plans had been made for a new one, but not carried through, as the Hedrett spaceport was close enough to make another one unnecessary. Gadrin maintained close ties with the platform city of Lissken.
Gadrin was led by a governor, who was supposed to be elected every four years. In actuality, votes for governor often passed with most citizens not even realizing it. The people of Gadrin had a general apathy when it came to government and politics. The governor of Gadrin in 31 BBY was Barnab Chistor. He enjoyed galactic culture, and imported as much as he could to Gadrin, such as holotheaters, concerts, and opera, spending public money though most citizens of Gadrin didn't attend those events. As Chistor enjoyed his job, he did nothing to correct the population's disinterest towards politics.
Around 32 BBY, Gadrin had a population of 20,000, including no more than 2,000 Tarasins. Hedrett had less inhabitants, but a greater Tarasin population. 
In 31 BBY, there were a series of pirate attacks on the various trade houses within Gadrin and Hedrett. These had been secretly arranged by Velin Wir of the Metatheran Cartel. On the 200th anniversary of Reidi Artom's settlement of Gadrin, a huge celebration was thrown in the town. This celebration was interrupted by a hologram of Wir, announcing the Cartel's plans for a trading and distribution center on Cularin.
The pirates were soon traced to a platform out in the jungles near the already built Metatheran Cartel jungle base. Though no proof connected the Cartel to the pirates, concerned citizens of the twin towns removed themselves from their daily lives and came together in a secret resistance movement against the Cartel. The Cartel suspected something was amiss, and armed Cartel guards were seen patrolling the streets, causing people to become nervous that they were returning to a time akin to when the Trade Federation was in control.
When the Cartel's jungle base was destroyed and the Cartel withdrew from the planet, another celebration was thrown in the streets of Gadrin. During this celebration, a vote was held to determine if the Cartel would be allowed to reestablish offices on the surface of Cularin. The vote ended in a dead tie, so Governor Chistor decided the matter, refusing the Cartel's request.
Later in 31 BBY, the system's crime lord Nirama recruited prospective employees using a landing platform 500 meters west of Gadrin. Even later that year, dark Jedi Karae Nalvas did the same twice in a local restaurant known as Bath Rabbud's. Nalvas's enemy Alec, a Jedi Knight, also booked a table there to gather and brief his allies against Nalvas.
- Gadrin Dump
- Gerrare household
- House Hirskaala compound
- Jedi Enclave
- Metatheran Cartel operations office
- Office of Peace and Security central office
- Office of Peace and Security third sector precinct house
- Reidi Artom museum and statue
- Renna's Transport Service compound
- The Chasm
- Vanster Enan's Sop House
- Unnamed laundry service
- A Cularin Presence
- The Resistance Within
- A Revelation
- An Uneasy Peace
- Head in the Clouds
- Clouded Paths (Indirect mention only)
- Into the Storm Clouds (Indirect mention only)
- Oblivion's Kiss
- Find the Lady
- Force Concession
- Force Contention
- (Mentioned only)
- Plea Bargain