This essay traces the emergence of African-American ethnicity and the subsequent evolution of the color line in five topics: Origins of African-American Ethnicity explains how the imposition of a unique endogamous color line eventually led to the synthesis of a unique ethno-cultural community in the Jacksonian Northeast. African-American Ethnic Traits outlines the customs of the Black Yankee ethnic group to show that they gave birth to many of today’s Black traditions. The Integration versus Separatism Pendulum introduces a debate that has occupied Black political leaders since colonial times. The Color Line in the North contrasts the harsh enforcement of the intermarriage barrier in the free states with the more permeable systems of the lower South (as presented in the preceding three essays). The National Color Line’s Rise and Fall concludes this section on the endogamous color line by presenting two graphs. The first shows that which side of the endogamous color line you were on was most hotly contested in U.S. courts between 1840 and 1869. The second shows that the color line grew abruptly stronger during Reconstruction, was at its harshest during Jim Crow, and began to recover only around 1980.