Kottayam (IPA: [ko:ʈ:ayam]) is a city in the Kottayam district of Kerala, India. It is the district headquarters of the district and is located about 151 km (93.8 mi) north of the state capital Thiruvananthapuram. As per the 2011 Indian census, Kottayam has a population of 489,615 people, and a population density of 4,533/km (11,740/sq mi). The total Kottayam Metropolitan area (the combined area of Kottayam municipality and its adjacent suburbs) has a population of 802,419 people, and a population density of 3,647/km (9,450/sq mi).

Kottayam is also referred to as "the City of Letters" as many of the first Malayalam daily newspapers, such as Deepika, Malayala Manorama, and Mangalam, were started and are headquartered in Kottayam, as are a number of publishing houses.

The royal palace of the Thekkumkur ruler was protected by a fort called Thaliyilkotta. It is believed that the name Kottayam is derived from a combination of the Malayalam words kotta which means fort (Thaliyilkotta) and akam which means inside. The combined form, Kottaykkakam (കോട്ടയ്ക്കകം), can be translated as "inside the fort".

From the beginning of the ninth century AD, the history of Thekkumkur and of Kottayam are virtually indistinguishable. Kottayam was then a part of Vempolinad, an area in the Kulashekara Empire (800 AD – 1103  AD). By 1103, the Kingdom of Vempolinad had split into the Kingdoms of Thekkumkur and Vadakkumkur, and the latter became a vassal of Cochin.

The royal house had originally been situated in Vennimala in Kottayam. It was protected by a fort known as Thaliyilkotta and, as a result, the locality came to be known by the same name as the fort. Afterward, Thekkumkur kings shifted their capital to Nattassery near Kumaranallore at the outskirts of Kottayam town. It is believed that the Thekkumkur dynasty ruled Kottayam from Thazhathangadi. Rulers of Munjanad and Thekkumkur had their headquarters at Thazhathangadi in the present Kottayam town. Marthanda Varma of Travancore attacked Thekkumkur and destroyed the palace and the Thaliyil fort. The remnants of the palaces and forts are still seen here.

The Portuguese and the Dutch established trade relations with both of these kingdoms, dealing in black pepper and other spices. After the subjugation of the Dutch East India Company by the Kingdom of Travancore in the 1741 Travancore–Dutch War, military operations of Marthanda Varma progressed against the northern neighboring kingdoms, including Thekkumkur.

Though Thekkumkur allied with Chempakassery and Vadakkumkoor to protect the kingdom, all of them were finally annexed to Travancore. Another source states that the ruler of Thekkumkur had sided first with the Kingdom of Kayamkulam and then with the principality of Ambalapuzha against Travancore. After the fall of Ambalapuzha, and as the ruler of Thekkumkur refused to come to terms with Travancore, his capital city was taken on 11 September 1750 by Ramayyan Dalawa, the general and prime minister of Marthanda Varma, and the state was annexed to Travancore in 1753.

By the early 19th century, Travancore became a Protectorate of Britain after a series of unfair treaties. In 1817, the Church Missionary Society established CMS College as the first Western-style college in Kerala. It was welcomed by the Travancore government to provide administrators for the public bureaucracy.

Kottayam has played its role in all the political agitations of modern times. The ‘Malayali Memorial ‘ agitation may be said to have had its origin in Kottayam. The Malayali Memorial sought to secure better representation for educated Travancoreans in the Travancore civil service against persons from outside. The Memorial, which was presented to the Maharaja Sri Moolam Thirunal (1891) was drafted at a public meeting held in the Kottayam Public Library. The event marked the beginning of the modern political movement in the State.

It was here that the famous Vaikom Satyagraha (1924–25), an epic struggle for eradication of untouchability, took place. Scheduled castes and other backward classes in Travancore were denied not only entry into temples, but also access to temple roads. Vaikom, the seat of a celebrated Siva Temple, was the venue of the symbolic satyagraha. Due to these protests, the Maharaja Chithira Thirunal Balarama Varma issued the Temple Entry Proclamation in 1936.

Kottayam became a revenue division of Travancore. A fifth division, Devikulam, existed for a short period but was later added to Kottayam. At the time of the integration of the State of Travancore and Cochin in 1949, these revenue divisions were redesignated as districts and the Diwan Peshkars gave way to district collectors, with the Kottayam district established in July 1949.

Kottayam has an average elevation of 3 metres (9.8 ft) above sea level. It is situated in the basin of the Meenachil River and in the basin of the Vembanad backwaters, which are formed from several streams in the Western Ghats of the Idukki district. The town is situated near the inland estuary of Meenachil river where it empties into the Vembanad lake in Kumarakom.

According to the division of places in Kerala based on altitudes, Kottayam is classified as a midland area. The general soil type is alluvial soil. The vegetation is mainly tropical evergreen and moist deciduous.

Under the Köppen climate classification, Kottayam has a Tropical monsoon climate (Am).

The climate in this district is moderate and pleasant. Kottayam's proximity to the equator results in little seasonal temperature variation, with moderate to high levels of humidity.

Kottayam district is bordered by Pathanamthitta district on the south, Alappuzha district on the west, Ernakulam district on the north and Idukki district on the east and northeast.

Historical population

Year	Pop.	±%
1901	17,552	—
1911	15,141	−13.7%
1921	18,833	+24.4%
1931	25,236	+34.0%
1941	33,364	+32.2%
1951	44,204	+32.5%
1961	52,685	+19.2%
1971	59,714	+13.3%
1981	64,431	+7.9%
1991	89,625	+39.1%
2001	129,894	+44.9%
2011	172,878	+33.1%

As of 2001 India census, Kottayam Urban Agglomeration had a population of 172,878, while Kottayam district had a population of 1,974,551. The population of Kottayam municipality was 136,812. Males constituted 62% of the population and females 38%. Population growth in the district had a diminishing trend with a decadal population growth rate of 6.5% compared to 9.35% across the decade 1991–2000. Population growth in the municipality is due to migration for employment. Kottayam District is ranked first in literacy, with 95.9% literacy compared to 90.92% for Kerala State and 65.38% for India (2001 census).

Scheduled Castes and Scheduled Tribes constituted 6.73% and 0.31% of the total population in Kottayam respectively. 19,739 persons were engaged in work or business activity, including 14,282 males and 5,457 females. In the census survey, the worker is defined as a person who does business, job, service, cultivator or labour activity. Of total 19,739 working population, 90.17% were engaged in main work while 9.83% of total workers were engaged in marginal work.

Jnananikshepam was the first newspaper published by the natives of Kerala, published at CMS press at Kottayam in 1848. Kottayam has produced many well-known writers, journalists and artists. Novelist Muttathu Varkey and poet Pala Narayanan Nair both have roots in Kottayam. Kottayam Pushpanath, a writer of crime thrillers lives in Kottayam. The Indian-English novelist Arundhati Roy is a native of Kottayam and her semi-autobiographical Booker Prize-winning novel, The God of Small Things, contains her childhood experiences in Aymanam, Kottayam. Unni R. a story writer and scriptwriter, is also from Kottayam. Kottayam was the first town in India to have achieved 100% literacy. Kottayam Public Library was founded in 1882 by T Rama RaoDewanPeshkar (Collector) of Northern Division of Travancore State.

In the 17th century, a Dutch school was started at Kottayam, which was short-lived. The first English school in Kerala, and the first college in India, was established in 1817 by the Church Missionary Society of England under the leadership of Col. John Munro, as CMS College. Later in 1891, the clergies of Catholic Church, under the leadership of Fr Charles Lavigne, established St Berchmans English High School, Changanassery, one of the first residential English High School in Central Travancore. On seeing a need for instituition for higher education in Kottayam - Malabar region, under the leadership of Venerable Mar Thomas Kurialacherry, Bishop of Archeparchy of Changanassery with help of Syro Malabar Catholic Church, established the famous SB College in Changanasserry in 1922. Today CMS College Kottayam and SB College Changanasserry stands as a landmark and has made a huge contribution to education in the district. Thus, Kottayam became India's first town with 100% literacy in 1989.

The Government Medical College, Kottayam, is one of the most prominent medical colleges in Kerala. Mahatma Gandhi University, Kerala, is based out of Kottayam. Kottayam boasts several other colleges and universities.

There are 14 engineering colleges. Government Engineering College, Rajiv Gandhi Institute of Technology, Kottayam is located in Pampady, 14 km east of Kottayam. Indian institute of information technology, Kottayam is an institute of national importance is also located around 30 km (19 mi) from Kottayam, near to Pala town. Indian Institute of Mass Communication (IIMC) also has one of its regional centres based at Kottayam.

In 1821, Benjamin Bailey, a British missionary, established C.M.S. Press, the first printing press in Kerala, in Kottayam. The town has been at the forefront of newspaper and book publishing in the state ever since.

Newspaper Malayala Manorama, published from Kottayam, is one of the largest circulating dailies in India. The Malayala Manorama Group, based in Kottayam, also owns Manorama Online, Manorama News Channel, The Week magazine and other publications. Other major Malayalam newspapers—Mathrubhoomi, Deshabhimani, Deepika, Madhyamam, and around thirty periodicals are published from Kottayam. Kottayam is also home to several Malayalam book publishers such as D. C. Books, Labour India Publications and Current Books. Almost 70 percent of books published in Kerala are from Kottayam. In 1945, a group of writers set up Sahithya Pravarthaka Sahakarana Sangham (English: Literary Workers' Co-operative Society) in Malayalam.

A number of annual basketball tournaments including the Marian Trophy, Girideepam Trophy, Lourdes Trophy and Virginia Memorial Tournament are conducted. The main sports stadiums in Kottayam are Nehru Stadium and Rajiv Gandhi Indoor Stadium, both located in Nagambadom and Native Ball (നാടൻ പന്തുകളി) well known sports in Kottayam.

Kottayam is one of the six municipalities in the district, formed after the implementation of the Kerala Municipalities Act in 1994. The members of the municipal council are elected from each of 52 wards every five years, held with the local government elections across the state. The chairperson is the executive authority of the municipality.

Kottayam city is the part of the Kottayam legislative assembly constituency and the Kottayam Lok Sabha constituency. The legislative assembly election is conducted every four years, last in May 2016.