Karaikudi comes under the Karaikudi assembly constituency, which elects a member to the Tamil Nadu Legislative Assembly once every five years, and it is a part of the Sivaganga (Lok Sabha constituency), which elects its member of parliament (MP) once in five years. The city is administered by the special grade Karaikudi municipality, which covers an area of 33.75 km2 (13.03 sq mi). As of 2011, the city had a population of 106,714. Roadways are the major mode of transportation to Karaikudi and the nearest airport is Madurai Airport, located 80 kilometres (50 mi) away from the city.
The town derives its name from thorny plant Karai referred in ancient literature as Kareekudi, which in modern times became Karaikudi. The town was established in the 19th century, and the oldest known structure is the Koppudaiya Nayagi Amman Temple. Mahatma Gandhi delivered two speeches in Karaikudi in 1927 and Bharathiyar visited Karaikudi in 1919 to participate in a function. Post independence, the town registered significant growth in the industrial sector. Karaikudi and surrounding areas are generally referred as "Chettinad". The town is home to Nagarathar, a business community and Chettiars, financiers and trade facilitators.
According to 2011 census, Karaikkudi had a population of 106,714 with a sex-ratio of 1,000 females for every 1,000 males, much above the national average of 929. A total of 10,619 were under the age of six, constituting 5,405 males and 5,214 females.The average literacy of the town was 81.48%, compared to the national average of 72.99%. The town had a total of 27504 households. There were a total of 40,069 workers, comprising 244 cultivators, 314 main agricultural labourers, 1,303 in household industries, 30,836 other workers, 7,372 marginal workers, 62 marginal cultivators, 496 marginal agricultural labourers, 345 marginal workers in household industries and 6,469 other marginal workers.
Karaikudi is located in Sivagangai district of Tamil Nadu State. The Trichy–Rameswaram Highway passes through Karaikudi. The Thennar River flows through South Karaikudi. Karaikudi is located at 10.07°N 78.78°E / 10.07; 78.78. It has an average elevation of 82 metres (269 ft). The terrain of Karaikudi is predominantly flat. Rocky areas are found in the surrounding areas of Karaikudi town and intensity of rocks is more towards western side of the town. The soil is hard red lateritic type and is not suitable for cultivation. The water table in the area is generally at depths of 3 to 6 ft (0.91 to 1.83 m) and rises to nearly 1 m (3 ft 3 in) below the ground level during rainy seasons. Since the 1970s, the water supply for the Karaikudi residents has been dependent on the deeper aquifers. The average maximum temperature is about 34 °C (93 °F), and average minimum temperature is about 24 °C (75 °F). The annual average rainfall in Karaikudi is about 920 millimetres (36 inches).
Karaikudi was constituted as a municipality in 1928 and was upgraded to Grade II Municipality in 1973, to Selection Grade in 1988 and special grade in 2013. The area of municipality is about 13.75 km2, comprising the revenue villages of Kalanivasal, Sekkalai kottai, Elappakudi Area, Ariyakudi Area and Senjai. The Karaikudi municipality has 36 wards and there is an elected councillor for each of those wards. The functions of the municipality are devolved into six departments: general administration/personnel, Engineering, Revenue, Public Health, city planning and Information Technology (IT). All these departments are under the control of a Municipal Commissioner who is the executive head. The legislative powers are vested in a body of 36 members, one each from the 36 wards. The legislative body is headed by an elected Chairperson assisted by a Deputy Chairperson.
Karaikudi is a part of the Karaikudi assembly constituency and it elects a member to the Tamil Nadu Legislative Assembly once every five years. From the 1977 elections, All India Anna Dravid Munnetra Kazhagam (AIADMK) won the assembly seat four times (in 1977, 1984, 1991 and 2009 elections), two times by Dravida Munnetra Kazhagam (DMK, 1980 and 1989), once by Tamil Maanila Congress (TMC, 1996) and twice by Indian National Congress (INC) won during 2006, 2016 elections. The current member of the constituency is K. R. Ramasamy from the Congress party. Karaikudi is a part of the Sivaganga Lok Sabha constituency. The current Member of Parliament from the constituency is P. R. Senthilnathan from the AIADMK. From 1967, the Sivangang parliament seat was held by the Indian National Congress for eight times (during 1980, 1984, 1989, 1991, 1999, 2004 and 2009 elections), ADMK once (during 1977 elections), Tamil Maanila Congress twice (during 1996 and 1998 elections) and Dravid Munnetra Kazhagam twice (during the 1967 and 1971 elections).
Law and order in the city in maintained by the Sivaganga sub division of the Tamil Nadu Police headed by a Deputy Superintendent. There are three police stations in the town, one of them being an all-women police station. There are special units like prohibition enforcement, district crime, social justice and human rights, district crime records and special branch that operate at the district level police division headed by a Superintendent of Police.
Kundrakudi Shanmuganathan Temple, located 8 km (5.0 mi) away, Ariyakudi Thiruvengamudayan Temple located 3 km (1.9 mi) away, Pillayarpatti Karpagavinayagar temple located 10 km (6.2 mi) away, Thirumayam Permual Temple located 22 km (14 mi) away from Karaikudi are the prominent temples around the town. Kannadasan Mandapam, Kamban Manimandapam, Thousand windows house and Chettinad Raja Palace are other visitor attractions in Karaikudi. The first Temple for Mother Tamil is located in Karaikudi and was established in 1993. Chettinad cuisine originated in the areas around Karaikudi.
Karaikudi is a developing urban center in Sivaganga district in Tamil Nadu. UNESCO has offered to set up a Chettinad Heritage Museum in Sivaganga district recognizing the unique style of architecture in the region. Chettinad Kottan are Palm leaf baskets woven by the women of the region. Chettinad Kottan has been noted for its unique style and colors and was granted a Geographical Indication tag in 2013. Chettinadu Kandangi sarees are a popular type of sarees produced in the region. Athangudi tiles are basically cement tiles like mosaic used for building the palatial houses in the town and in modern times, is a source for handicraft industry. Indian Overseas Bank was founded on 10 February 1937 in Karaikudi by M. Ct. M. Chidambaram Chettyar.
The town has two bus terminals namely "Old Bus-stand" and "New Bus-stand". Buses that connect the nearby villages and smaller towns terminate at the Old bus-stand. The State Transport Corporation run moffusil buses terminate at the New bus-stand. Karaikudi Junction railway station is the major railhead serving the town. Nearby airports include Tiruchirapalli International Airport (95 kilometres (59 mi)) and Madurai International Airport (100 kilometres (62 mi)).
As of 2011, there were 18 government and private schools in Karaikudi and five colleges in the town. Alagappa Chettiar College of Engineering and Technology is the oldest college and was established in 1953. Electricity supply to Karaikudi is regulated and distributed by the Tamil Nadu Electricity Board (TNEB). The town along with its suburbs forms the Sivaganga Electricity Distribution Circle. Water supply is provided by the Karaikudi Municipality from seven borewells is located at Sambai Oothu (Artesian aquifer). As per the municipal data for 2011, about 45 metric tonnes of solid waste were collected. There is no underground drainage system in the town and the sewerage system for disposal of sullage is through septic tanks, open drains and public conveniences. The municipality maintained a total of 46.55 km (28.92 mi) of storm water drains in 2011. As of 2011, there was one government hospital and 13 private hospitals in the town. The municipality operates two markets, namely the Anna Daily Market and Uzhavar Santhai that cater to the needs of the town and the rural areas around it.