Which states were considered the exporting hubs for slaves in the 19th century?

The states of Maryland, Virginia, and North Carolina were indeed significant exporting hubs for slaves in the 19th century. These states were part of what is often referred to as the "Upper South," where the practice of slavery was firmly established, although these states were not as prominent as the Deep South in terms of cotton production later on.

During this period, Virginia, in particular, was a major supplier of enslaved people, as it had a well-established infrastructure of slavery and a surplus of enslaved individuals due to its aging agricultural economy that was shifting from tobacco to other crops. Many enslaved people were sold from these states to the Deep South, especially for cotton cultivation, as demand surged in the early 19th century. Maryland and North Carolina also contributed significantly to this slave trade through internal sales and trafficking.

In contrast, while states like Texas and Louisiana were heavily involved in slaveholding and agriculture, they were more focused on exploiting the labor of enslaved people rather than exporting them in the volume seen from the Upper South. Other states like Georgia and South Carolina had their own agricultural systems, but they were less involved in the direct exporting of slaves compared to the states mentioned in the correct answer.