The census is a once-in-a-decade survey that gives the most accurate estimate of all the people and households in England and Wales. It has been carried out every decade since 1801, with the exception of 1941.
It will be the first run predominantly online, with households receiving a letter with a unique access code, allowing them to complete the questionnaire on their computers, phones or tablets.
The census will include questions about your sex, age, work, health, education, household size and ethnicity. And, for the first time, there will be a question asking people whether they have served in the armed forces, as well as voluntary questions for those aged 16 and over on sexual orientation and gender identity.
Results will be available within 12 months, although personal records will be locked away for 100 years, kept safe for future generations.