Gachsaran County (Persian: شهرستان گچساران, Persian pronunciation: [ɡatʃsɒːrɒːn]) is in Kohgiluyeh and Boyer-Ahmad province, Iran. Its capital is the city of Dogonbadan.

This city was named Gonbad-e Malghan or Gonbad-e Maljan in the past and now Dogonbadan and Gachsaran. There were two domes, one to the west and one to the east of the city, so the city was called Do Gonbadan ("between two domes"). The city was rebuilt by British staff of the Darcy Oil Company about 1927. It is reported that this area was also populated with some British residents who owned houses and vast lands not far from the outskirts of the city.

After the 2006 National Census, Basht District was separated from the county in the establishment of Basht County.

At the time of the 2006 census, the county's population was 131,628 in 28,551 households. The following census in 2011 counted 119,217 people in 30,399 households. The 2016 census measured the population of the county as 124,096 in 34,329 households.

Gachsaran County's population history and administrative structure over three consecutive censuses are shown in the following table.

Gachsaran County Population

Administrative Divisions	2006	2011	2016
Central District	109,458	118,022	123,370
Bibi Hakimeh RD	1,789	1,763	1,370
Boyer Ahmad-e Garmsiri RD	4,709	3,794	3,390
Emamzadeh Jafar RD	12,817	12,203	13,339
Lishtar RD	8,241	8,523	8,543
Dogonbadan (city)	81,902	91,739	96,728
Basht District	22,170
Babuyi RD	9,606
Kuh Mareh Khami RD	4,295
Basht (city)	8,269
Total	131,628	119,217	124,096
RD = Rural District

Gachsaran is an oil- and gas-producing area that has just started to expand and profits from its industrial capacity. Gachsaran has the largest gas reserves in Iran also has the largest recoverable oil field in Iran and third in the world and has good various medicinal plants, citrus and olive. This city has good weather in middle and end of winter also has nice mountains for climbing around the city so it is perfect destination for climbing in fall, winter and beginning of spring. This city has good water resources and there are two big dams near the city which export water to other cities.

This county is known as Iran's oil roof because of the highest oil tower located in this county (Seghalatoun, 3221 feet above sea level) one of the most important and richest areas but more unknown in Iran because of its oil and gas products and it has the second largest (Ahvaz has the first) oil fields of Iran in this county. This county is one of the main heart of energy resources in the world. More than one-quarter of the oil of Iran is exported to all over the world from this county.. This Country is one of the special economic zones of Iran

The Gachsaran Oil & Gas producing company with a distinct geographical situation stretches over provinces of Kohgiluyeh and Boyer-Ahmad Province, Fars, Busher, Khuzistan and Isfahan. Total production from about 320 wells is 750,000 bd. The main wells have been drilled at reservoirs of Gach Saran, Bibi Hakimeh, Rag-e-Safid, Pazanan, Gulkhari, Binak, Chilingar, Nargesi, Garangan, Kilur Karim, Sulabedar, Siahmakan, Khaviz, Rudak, Zaaeh, Chahr Bisheh and Kuh-e-kaki.

Out of these regions Gachsaran Reservoir with 500,000 bd and Siahmakan with 4000bd have the highest and lowest production rates respectively.

Gachsaran and Dogonbadan as names of a city are in fact referring to the same place, as the city has two names.

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  British staff of an oil company in Gachsaran in 1957
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  Keyvan Falls in Gachsaran

Media related to Gachsaran County at Wikimedia Commons

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