George,

I've heard the statement that there were more anti-slavery groups in the South than the North, but I can't remember where. I do not believe it was the case...certainly not in the years immediately preceding the war.

By the 1850s, slavery was such a sensitive issue in the South that even appearing apathetic to its preservation (at least publicly) was deemed nearly traitorous. There are some interesting books related to this subject, including Lacy Ford's "Origins of Southern Radicalism," J. Mills Thornton's "Politics and Power in a Slave Society: Alabama, 1800-1860," and William J. Cooper's "The South and the Politics of Slavery, 1828-1856." Among the topics these books cover is the increasing defense of slavery in the South in the 1850s, to where politicians of both parties in the Deep South would often try to one-up each other in just how "Southern" they were with their defense of slavery. Antislavery material was banned from many parts in the South (sometimes publicly burned, such as pamphlets and books). The defense of slavery became so powerful that even religious denominations in the South which had earlier challenged the morality of slavery broke from their northern counterparts and adapted to accept slavery, which is why there are "Southern" branches of the Baptist and Methodist churches.

Now, there were Southerners who came to oppose slavery, such as the Grimke sisters. By the mid-19th century, however, they traveled or moved north to carry out their campaigns. They were often quite popular and powerful in antislavery circles as "converts" or "witnesses" to the institution.

Most of this extreme defense of slavery really developed after around 1830. I cannot off the top of my head recall any antislavery societies or groups in the South before then, but I would not be surprised if they had previously been present and perhaps even strong.