"Population Profiles, Vol. 3" contains modifications which were made in order to update the second volume in this trilogy. Adjustments were also made when research revealed major 1970 census report inaccuracies. Demographic and socioeconomic characteristics of the populations resident in 114 smaller school districts in Washington State are presented. Demographic data for reference use in educational programs in the State are detailed. Tabular demographic and socioeconomic data from the 1970 U.S. Census are given for each of 114 smaller school districts, as well as the State as a whole. Particular emphasis is placed on needs assessment data required by the Urban, Racial, and Rural Disadvantaged Programs of the Office of the State Superintendent of Public Instruction. The demographic and socioeconomic profiles are also designed to be of value in administering other categorical aid programs, as well as a wide variety of educational and curricular programs. The majority of the document is comprised of statistical tables and charts. (Author/AH)