Projections of the number of 18-year-olds in each Pennsylvania county through 1994 are presented. The projections are further disaggregated by the student attributes of sex and race. The projections are based on historical migration rates, natality rates, and mortality rates. The projection procedure assumes that the survival and migration rates remain constant across cohorts; however, there will be deviations between projected and actual numbers of 18-year-olds. The importance of the projections does not depend on this absolute accuracy, but upon the overall trends that are revealed. The projections provide a basic input for determining the potential number of first-time students available in the traditional college-age cohort. The data on the total statewide projections for Pennsylvania between 1971 and 1994 show that the number of 18-year-olds remained a relatively constant 255,000 between 1973 and 1977; however, the decline in the number of 18-year-olds begins in 1978. During the 1980s, the total number of 18-year-olds will decline 19.6 percent. Over the period 1971-1994, the decline in the number of 18-year-olds is projected to be 34.5 percent. Problems that will affect the conversion of demographic declines into college enrollments include predicting: the number of 18-year-olds eligible to go to college (i.e., who actually graduate from high school); the number of eligible students who choose to attend college; the number of nontraditional students, including part-time adult students; and college student retention rates. In addition to the projection statistics, the projection formula and a bibliography are presented. (SW)