An analysis of population and public school enrollment trends in Colorado counties from 1960 to 1979 is described in this report, and simplified methods for projecting future enrollments on the basis of the historical data are provided. Population and enrollment trend data for Adams County are included in the document as examples of the data developed during the study, but similar data for the other Colorado counties must be obtained separately. The information provided in the five tables on Adams County includes census figures and estimates of population for the years analyzed, fall school enrollment figures, and percentages of annual change in these data; fall grade level enrollments as percentages of total school enrollment; numbers that can be used as multipliers to figure the relationships between each grade level and the next lower level during any given year; and numbers that can be used as multipliers to figure enrollment change as cohorts move from one grade level to the next in succeeding years. (PGD)