Every 10 years the Office for National Statistics (ONS) carries out a census of everybody in England and Wales.
The 2011 census asked about work, health, national identity, ethnic background, education, second homes, language, religion, marital status and more.
The statistics from the responses are used to build a picture of today's society.
Results and comparison to 2001 census
The results showed that the usually resident population for Cambridge in 2011 was 123,900. This was an increase of about 15,000 (13%) since 2001.
The number of households in Cambridge increased by 4,042 (9.5%) since 2001.
The population continued to show a 'bulge' in the number of people in the 16 to 24 and 25 to 39 age groups. This reflects the large number of students resident in the city.
Overall, the population of Cambridge had aged slightly. The increase in the number of older people, as a proportion of the population, wasn't as high as in other areas.