This paper documents how segregation between blacks and whites across colleges in the United States has evolved since the 1960s.  It also explores potential explanations for the trends.  The main findings are as follows: (1) White exposure to blacks has been rising since the 1960s, whereas black exposure to whites increased sharply in the late 1960s and early 1970s and has fluctuated since then.  Meanwhile, black-white dissimilarity fell sharply in the late 1960s and early 1970s and has fallen more gradually since then.  (2) There has been regional convergence, although colleges in the South remain more segregated than those in any other region when measured by dissimilarity or by black exposure to whites.  (3) A major channel for the decline in segregation, especially in the South, is the declining share of blacks attending historically black colleges and universities.  (4) Recent statewide affirmative action bans by some states may actually be reducing racial segregation.