Complete data on the basic demographic characteristics of the inhabitants of the United States from the 1980 Census of Population are presented in this report. Eleven pages of maps and charts show information on various geographical regions of the United States (regions, divisions, standard metropolitan statistical areas, standard consolidated statistical areas, and urbanized areas) and data on age, sex, race, Spanish origin, family type, and marital status. The greater part of the report consists of 38 detailed tables giving data in the same categories. In general, the amount of data is greater for the United States than for the states and smaller geographical areas. Data from earlier censuses are shown for the United States. Five additional tables deal with substitutions and allocations. Appendixes give information on the following: area classifications; definitions and explanations of subject characteristics; residence rules and data collection and processing procedures; a description of the allocation and substitution tables; copies of the respondent instructions and 1980 census questionnaire pages including the 100 percent population questions; and a summary of the data dissemination program of the 1980 census. (CMG)