This paper presents estimates which indicate that about 2 million illegal aliens were included in the 1980 census. Of these, over 900,000 were born in Mexico. The estimates, derived with a residual method, are developed by comparing the census count of aliens with estimates of the legally resident alien population based on data collected by the Immigration and Naturalization Service in January 1980. Estimates are presented by age, sex, and period of entry for all aliens residing in the United States, for aliens from Mexico, and for other selected countries of origin. In addition to setting a lower limit on the number of undocumented aliens residing in the United States in 1980, the estimates provide a framework for assessing the possible maximum number of illegal aliens in the country, as well as providing data which are useful for evaluating the completeness of coverage of the 1980 census.

This paper presents estimates which show that 2 million undocumented aliens were included in the 1980 census. Of these, 1.1 million were born in Mexico. The estimates, derived with a residual method, are developed by comparing a census-based estimate of aliens with estimates of the legally resident alien population based on data collected by the Immigration and Naturalization Service in January 1980. Estimates are presented by age, sex, and period of entry for all aliens residing in the United States, for aliens from Mexico, and for other selected countries of origin. In addition to setting a lower limit on the number of undocumented aliens residing in the United States in 1980, the estimates provide a framework for assessing the total number of undocumented aliens in the country.

This paper presents estimates which indicate that about 2 million illegal aliens were included in the 1980 census. Of these, over 900,000 were born in Mexico. The estimates, derived with a residual method, are developed by comparing the census count of aliens with estimates of the legally resident alien population based on data collected by the Immigration and Naturalization Service in January 1980. Estimates are presented by age, sex, and period of entry for all aliens residing in the United States, for aliens from Mexico, and for other selected countries of origin. In addition to setting a lower limit on the number of undocumented aliens residing in the United States in 1980, the estimates provide a framework for assessing the possible maximum number of illegal aliens in the country, as well as providing data which are useful for evaluating the completeness of coverage of the 1980 census.