This research brief reviews trends over two decades in enrollment and baccalaureate degrees at public universities that meet the Carnegie Classification definition for "doctorate-granting" and "comprehensive." Opening highlights note that public universities comprise nearly 25 percent of the nation's four year colleges and universities and that these institutions saw an enrollment increase of 38 percent between 1970 and 1990. A side-bar covering a full page explains the Carnegie institutional classification system and the definitions of comprehensive and doctorate-granting universities. Sections on enrollment, baccalaureates, and numbers and distribution of institutions follow. Some findings are: (1) there were 459 doctorate granting and comprehensive public universities in 1987; (2) geographic distribution of these institutions shows a pattern repeated in the enrollment and earned degree data with 65 percent of universities east of the Mississippi; (3) geographic distribution of public universities' 5.5 million students in Fall 1990 mirrors the distribution of the nation's population; (4) the share of national enrollments accounted for by public universities has not changed significantly in the 1970-1990 period; and (5) of the 5.5 million students at public universities 52 percent are enrolled in doctorate-granting institutions and 48 percent at comprehensive institutions. A conclusion section suggests that institutions in areas where a decline in the traditional student population is predicted should carefully examine their clientele populations and missions. (Contains nine references.) (JB)