Slave traders used the Alabama River to deliver slaves to planters as laborers to work the cotton. Buoyed by the revenues of the cotton trade at a time of high market demand, the newly united Montgomery grew quickly. In 1822, the city was designated as the county seat. A new courthouse was built at the present location of Court Square, at the foot of Market Street (now Dexter Avenue). Court Square had one of the largest slave markets in the South. The state capital was moved from Tuscaloosa to Montgomery, on January 28, 1846.