thumb|On this map of the various enclaves, east is at the top of the map. India is shown in orange, and Bangladesh is cyan.
The India–Bangladesh enclaves, also known as the Chiṭmahals ( chiṭmôhôl) and sometimes called Pasha enclaves, were the enclaves along the Bangladesh–India border, in Bangladesh and the Indian states of West Bengal, Tripura, Assam and Meghalaya. The main body of Bangladesh contained 102 Indian enclaves, which in turn contained 21 Bangladeshi counter-enclaves, one of which contained Dahala Khagrabari, an Indian counter-counter-enclave, the world's only third-order enclave when it existed. The Indian mainland contained 71 Bangladeshi enclaves, which in turn contained 3 Indian counter-enclaves. A joint census in 2010 found 51,549 people who were residing in these enclaves: 37,334 in Indian enclaves within Bangladesh and 14,215 in Bangladeshi enclaves within India.
The Prime Ministers of India and Bangladesh signed the Land Boundary Agreement in 1974 to exchange enclaves and simplify their international border. A revised version of the agreement was adopted by the two countries on 7 May 2015, when the Parliament of India passed the 100th Amendment to the Constitution of India. Under this agreement, which was ratified on 6 June 2015, India received 51 Bangladeshi enclaves (covering ) in the Indian mainland, while Bangladesh received 111 Indian enclaves (covering ) in the Bangladeshi mainland. The enclave residents were allowed to either continue residing at their present location or move to the country of their choice. The exchange of enclaves was to be implemented in phases between 31 July 2015 and 30 June 2016. The enclaves were exchanged at midnight on 31 July 2015 and the transfer of enclave residents was completed on 30 November 2015. After the Land Boundary Agreement, India lost around to Bangladesh.
Since the exchange of territory took place, the only remaining enclave is Dahagram–Angarpota, an exclave of Bangladesh.
History
According to a popular legend, the enclaves were used as stakes in card or chess games centuries ago between two regional kings, the Raja of Koch Bihar and the Maharaja of Rangpur.
After the partition of India in 1947, Rangpur was joined to East Pakistan. Cooch Behar State, with its exclaves and holes, was a native state, whose Raja had the option of joining either India or Pakistan. Cooch Behar district was merged in 1949 with India. The desire to "de-enclave" most of the enclaves was manifested in a 1958 agreement between Jawaharlal Nehru and Feroz Khan Noon, the respective Prime Ministers, for an exchange between India and Pakistan without considering loss or gain of territory. But the matter then worked into a Supreme Court case in India, and the Supreme Court ruled that a constitutional amendment was required to transfer the land, so the ninth amendment was introduced to facilitate the implementation of the agreement. The amendment could not be passed because of objections to the transfer of the southern Berubari enclave. Because of India's deteriorated relations with Pakistan, the issue remained unsolved. Negotiations restarted after East Pakistan became independent as Bangladesh in 1971 following the Bangladesh Liberation War.
Agreement
thumb|The diagramatic sketch of Cooch Behar district of West Bengal marking enclaves|400px
The Land Boundary Agreement was signed on 16 May 1974 between Indira Gandhi and Sheikh Mujibur Rahman which provided for the exchange of enclaves and the surrender of adverse possessions. Under the agreement, India retained the Berubari Union No. 12 enclave while Bangladesh retained the Dahagram-Angorpota exclaves with India providing access to it by giving a corridor, called the Tin Bigha Corridor. Bangladesh quickly ratified the agreement in 1974 but India failed to do so. The issue of the undemarcated land boundary of approximately in three sectors — Daikhata-56 in West Bengal, Muhuri River-Belonia in Tripura and Lathitila-Dumabari in Assam — also remained unsolved. The Tin Bigha Corridor was leased to Bangladesh in 1992 amid local opposition. Both nations announced an intention to swap 162 enclaves, giving residents a choice of nationality.
Under the agreement, India received 51 of the 71 Bangladeshi enclaves (from 51 to 54 of the 74 chhits) that were inside India proper (), while Bangladesh received 95 to 101 of the 103 Indian enclaves (111 out of 119 chhits) that were inside Bangladesh proper (). The people living in these enclaves without a nationality were allowed to choose their nationality.
The Constitution (119th Amendment) Bill, 2013 was introduced in the Rajya Sabha, the upper house of the Parliament of India, on 18 December 2013. Nationalist groups in Assam strongly opposed the bill, which would cause India to lose 40 km<sup>2</sup> (10,000 acres) of land, but Indian Prime Minister Narendra Modi supported it because it would make the border with Bangladesh easier to manage. The parliament panel, Standing Committee on External Affairs, approved the bill in November 2014. The Rajya Sabha approved the constitutional amendment on 6 May 2015, and the Lok Sabha approved it the following day. The exchange of enclaves and land parcels in adverse possession, and the boundary demarcation, was implemented in phases between 31 July 2015 and 30 June 2016. The enclaves were to be exchanged at midnight on 31 July 2015 and the boundary demarcation was to be completed by 30 June 2016 by Survey Departments of the respective countries. The transfer of enclave residents was expected to be completed by 30 November 2015.
Notable enclaves
thumb|300px|[[Dahala Khagrabari was the world's only third-order enclave. It was a piece of India within Bangladesh, within India, within Bangladesh. It was less than in area, and contained a field. (Maps)]]
Bangladesh
Dahagram–Angarpota: The largest Bangladeshi composite enclave (combining the first- and third-largest Bangladeshi chhits by area), administered as part of Patgram Upazila in Lalmonirhat Zila, lies within the Indian province of West Bengal. It is separated from the contiguous area of Bangladesh at its closest point by . The enclave has an area of with a resident population of 20,000 people. The enclave lacks basic facilities. The lone health complex remains virtually useless because of lack of power supply, as India refused to allow Bangladesh to run power lines to the enclave.
India
Dasiar Chhara, the fourth largest Indian chhit by area, was the largest stand-alone Indian enclave (i.e., not a composite of adjoining chhits). It lay from the main part of India and had an area of .
Dahala Khagrabari, enclave #51, was the world's only third-order enclave, being a piece of India within Bangladesh, within India, within Bangladesh. It was the site of a jute field, owned by a Bangladeshi farmer living in the Bangladeshi second-order enclave surrounding Dahala Khagrabari. As part of the 2015 border agreement, India ceded it to Bangladesh.
List of former enclaves and exclaves
Schematic overview:
{| width=40%
|- valign=top
| width=50% |
{| style="border-width: 3px; border-style: solid; text-align: center; background-color: #96decb;" cellspacing=10
| Bangladesh<br /><br />
{| style="border-width: 1px; border-style: solid; background-color: #ffcc99;" cellspacing=15
| 102 enclaves of India (69.5 km<sup>2</sup>)<br /><br />
{| style="border-width: 1px; border-style: solid; background-color: #96decb;" cellspacing=15
| 21 counter-enclaves of Bangladesh (2.1 km<sup>2</sup>)<br /><br />
{| style="border-width: 1px; border-style: solid; background-color: #ffcc99;" cellspacing=15
| 1 counter-counter enclave of India (0.007 km<sup>2</sup>)
|}
|}
|}
|}
| width=25 |
| width=50% |
{| style="border-width: 3px; border-style: solid; text-align: center; background-color: #ffcc99;" cellspacing=10
| India<br /><br />
{| style="border-width: 1px; border-style: solid; background-color: #96decb;" cellspacing=15
| 71 enclaves of Bangladesh (47.7 km<sup>2</sup>)<br /><br />
{| style="border-width: 1px; border-style: solid; background-color: #ffcc99;" cellspacing=15
| 7 counter-enclaves of India (0.17 km<sup>2</sup>)
|}
|}
|}
|}
Some individual enclaves were composed of several administrative units (chhits and/or mauzas). These administrative units must be differentiated from the enclave as a whole. "This is particularly important for the Cooch Behar enclaves, where the several administrative units which together form some of the larger enclaves are commonly, but wrongly, termed enclaves themselves, or where one component unit commonly lends its name to the whole enclave. ... [T]he official Indo–Bangladesh Boundary Commission figure of 111 Indian and 51 Bangladeshi exchangeable enclaves would appear to count only individual mauzas, even when these consisted of more than one enclave." imply that Purba Masaldanga (#86) and (#87) formed a single enclave. However, topographic mapping and other sources suggest two enclaves, as listed here, but if joined, they were connected across the narrowest gap separating them, along a beel (marshy former river course). are shown in parentheses, as (#). The India series is separate from the Bangladesh series. There were 37,334 people living in the Indian enclaves in 2015.
|-
| Banskata (#95)||0.0492
|||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Banskata (#89)||0.0484
|||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Gaochulka I||0.0361
|||First-order enclave within the Kurigram District of Bangladesh.
|-
| Dighaltari II||0.0357
|||First-order enclave within the Kurigram District of Bangladesh.
|-
| Najirgonja (#17)||0.0335
|||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Chenakata||0.0316 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Bara Khanki Kharija Gitaldaha (#53)||0.0312
|||First-order enclave within the Nilphamari District of Bangladesh.
|-
| Shingimari Part I||0.0246 ± 0.0013
|||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Kuchlibari (#57)||0.0234
|||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Jamaldaha Balapukhari||0.0212 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Najirgonja (#24)||0.0204 <big>†</big>
| <big>†</big>||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Nalgram Chhit||0.0191
|||Counter-enclave surrounded by a Bangladeshi exclave, Nalgram (#52), located within Cooch Behar District of West Bengal state, India.
|-
| Bara Kuchlibari||0.0176 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Najirgonja (#28)❋||0.01574
|||Part of Najirgonja composite exclave within the Panchagarh District of Bangladesh.
|-
| Najirgonja (#20)||0.01566 <big>†</big>
| <big>†</big>||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Bewladanga (#40)||0.01097
|||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Banskata (#103)||0.01032 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Chhit Seoruguri||0.01016
|||Smallest Indian counter-enclave, surrounded by a Bangladeshi true enclave/exclave, Madhya Masaldanga, located within Cooch Behar District of West Bengal state, India.
|-
| Banskata (#102)||0.00943 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Kuchlibari (#58)||0.00826
|||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Garati (#2)||0.00704
|||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Dahala Khagrabari (#51)||0.00688
|||Dahala Khagrabari (#51) is the only counter-counter enclave in the world. It is surrounded by Upanchowki Bhajni 110, a Bangladeshi counter-enclave within the Indian composite exclave named Balapara Khagrabari, which is surrounded by the Panchagarh District of Bangladesh. Dahala Khagrabari (#51) is not part of the Balapara Khagrabari composite exclave, as it is not contiguous to it and borders only Bangladesh.
|-
| Bhogramguri||0.00583 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Banskata (#106)||0.00563 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Banskata (#107)||0.00554 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Najirgonja Chhit (#30)❋||0.00433
|||Part of Najirgonja composite exclave within the Panchagarh District of Bangladesh.
|-
| Najirgonja (#22)||0.00421 <big>†</big>
| <big>†</big>||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Najirgonja (#21)||0.00413 <big>†</big>
| <big>†</big>||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Gaochulka II||0.00364
|||First-order enclave within the Kurigram District of Bangladesh.
|-
| Fulker Dabri||0.00356 <big>†</big>
| <big>†</big>||First-order enclave within the Lalmonirhat District of Bangladesh.
|-
| Bewladanga Chhat (#41)||0.00336 <big>†</big>
| <big>†</big>||First-order enclave within the Panchagarh District of Bangladesh.
|-
| Garati (#5)||0.00320
|||First-order enclave within the Panchagarh District of Bangladesh. Garati (#4) and (#5) are shown joined as one enclave in pre-1947 topographic maps, in which the smaller (#5) adjoins the northern boundary of the larger (#4). Later sources (1991 Indian census maps