This report presents detailed social and economic statistics for the population of the United States below the low-income level in 1973 based on the March 1974 Current Population Survey (CPS). Data are presented by selected characteristics such as race, family status, education, work experience, type and source of income, and residence in low-income areas. Several historical tables detailing a picture of the changing composition of the population below and above the low-income level since 1959, the first year for which low-income data are available, are also presented. In addition, this year, data are included on low-income persons by residence in the 10 Federal regions. Additional data on persons of Spanish origin, characteristics of families residing in poverty areas, and mobility status of families are also presented. In this text, the terms "low-income," "poverty," and "poor" are used interchangeably.