We estimate the numbers of young people aged 0 - 24 years, resident in the Northern Region in 1971, 1981, and 1991 by ethnic group, age, sex, and birth place (inside - outside the United Kingdom). In 1991 the numbers of residents by ethnic group, age, and sex were obtained from the census and adjusted for underenumeration; the numbers born inside and outside the United Kingdom were estimated from the 1991 Census Sample of Anonymised Records (SAR). In 1981 and 1971, the numbers of UK-born residents by ethnic group, age, and sex were estimated from the proportion of UK-born residents in the relevant group in the 1991 SAR; country of birth was used as an indication of ethnicity of non-UK-born residents. The accuracy of the estimates is assessed. The methodology developed could be applied to other regions of the United Kingdom.