The Spanish colonial government and the Roman Catholic religion provided the glue that over 400 years has welded Mexico’s fragmented population into a nation. In recent years, increased emigration, mostly to the United States, has slowed the growth of the population of both Mexico at large and Oaxaca. At about 98 million in 2000, Mexico’s population is growing at less than one percent per year, less than half the pace of previous decades. The same is true for Oaxaca’s population, which stood at about 3.4 million in the year 2000.

A growing population was not always the case in Mexico. Historians estimate that European diseases, largely measles and smallpox, probably wiped out as many as 20 million—perhaps 95 percent—of Mexico’s indígena population within a few generations after Cortés stepped ashore in 1519. Oaxaca’s population dropped correspondingly from a pre-conquest level of about two million to a mere 150,000 by 1650. Oaxaca’s native peoples, ironically, can look forward to the year 2019, five centuries after Cortés, when their population will have recovered approximately to its pre-conquest level.

By 1600, Mexico’s indigenous population had dropped so low that the Spanish began to import sizable numbers of African slaves, whose numbers swelled to several tens of thousands by 1650. Although much of the African lineage has been absorbed into Mexico’s general population, several thousand African Mexicans still maintain separate small communities in the Costa Chica, the coastal region spreading both east and west from the Oaxaca–Guerrero border.