Prior to independence, Kerala formed part of, the two Princely States of Travancore and Cochin and of Madras Presidency. The earliest authentic account of census in this part of India is available from the "Geographical and Statistical Memoir of the Survey of Travancore and Cochin States" conducted by Lieutenants Ward and Conner during the period 1816-20. Thereafter censuses were taken in Travancore State in 1836 and Cochin State in 1854. But there are grounds to believe that frequent attempts were made by the earlier rulers of the State to collect statistics of the population and the resources of the country.

The first modern census of Travancore - Cochin was taken in 1875. From 1881 onwards the constitutional units of Kerala State had census taken at 10 year intervals with the rest of the country. The first census of this State of Kerala was taken in 1961. Thereafter, census was taken every 10 years. The last census was taken in 2011.

Census 2011

Census 2011 put Kerala's population at 3,33,87,677 persons which included 16,021,290 males and 17,366,387 females. Although Kerala accounts for only 1 per cent of the total area of India, it contains about 3 per cent of the country's population. The population density of the state is about 859 people per square kilometres, three times the national average. Kerala is one of the densest States in the country and it recorded a decadal population growth of + 4.86% (1,546,303 persons). Kerala, with a sex-ratio (females per 1000 males) of 1084, is the only state in India with a positive figure. In the human development and related indices it occupies prime position among the Indian States.

          Malappuram is the most populated district and has a population of 41,10,956 people. Second comes Thiruvananthapuram with a population of 33,07,284 people followed by Ernakulam with 32,79,860 people. Wayanad is the least populated district followed by Idukki and Kasargod.Whereas, Thiruvananthapuram with a population density of 1509 persons per sq.km is the most densely populated district in Kerala followed by Alappuzha with 1501 people per sq.km and Kozhikode with 1318 persons per sq.km. Idukki with a density of just 254 persons per sq.km is the least densely populated district followed by Wayanad with a density of 383 persons. The average density of population of the state is 819 persons per sq.km.

          Kerala's urban population figures to 1,74,55,506 persons which is about one-fourth of the total population. Rural population in Kerala is 1,59,32,171. Of the total population of Kerala, working population (main and marginal workers) constitute 32.3% and non-workers form 67.7%.

          As per the Census 2001 data, Hindus, who constitute 56.20 per cent of the total population, is the most prominent religious community in the state. This is followed by Muslims who form 24.7 per cent of the population and Christians who constitute 19 percent of the total population. Also, a small number of Sikhs, Buddhists, Jains, Jews and other religious communities are also present.