The Rev. Henry Highland Garnett and Martin R. Delany, both prominent abolitionists, did much to advance the colonization/emigration movement. In 1858, Garnett formed the African Civilization Society with the aim of encouraging the concept of Black Nationalism. Though initially opposed to emigration, he came to the conclusion that African Americans had little chance of attaining true independence in their country. Blacks returning to Africa, he argued, could benefit continental Africans by bringing "civilization" and Christianity while gaining freedom for themselves. Garnett countered the argument that emigrationists were abandoning their enslaved comrades by stating that although he was totally opposed to that institution, "No man should deprive me of my love for Africa, the land of my ancestors." He also advocated migration to the Caribbean islands and spent several years as a missionary in Jamaica. In November 1882, Henry Highland Garnett, by then an old man, immigrated to Liberia, where he died soon after.

Martin Robison Delany was, perhaps, an even more forceful proponent of Black Nationalism than Garnett. He was a journalist, firebrand abolitionist, and one of Frederick Douglass's closest friends. Douglass said of him, "I thank God for making me a man, simply, but Delany always thanks Him for making him a black man." After a short and unpleasant stay at Harvard Medical School, Delany published The Condition, Elevation, Emigration and Destiny of the Colored People of the United States (1852), supporting black emigration.

The Condition, Elevation, Emigration and Destiny of the Colored People of The United States, Politically Considered by Martin Robison Delany

Vigorously opposed to the American Colonization Society because it was created by white men, he was an unbending advocate of black autonomy and self-reliance. Delany proposed the Caribbean islands, Canada, and Central America as alternative sites to Liberia. In 1859, he went to Africa to explore emigration possibilities and negotiated for an American settlement in Abeokuta (Nigeria), but nothing came of his effort. In 1877, Delany established the Liberian Joint Stock Steamship Line. The company's only voyage came a year later, when the ship Azor, carrying 206 migrants, sailed from Charleston to Liberia.

The Liberian Exodus. An Account of Voyage of the First Emigrants in the Bark “Azor,” and Their Reception at Monrovia, with a Description of Liberia—Its Customs and Civilization, Romances and Prospects: Electronic Edition. by Williams, Alfred Brockenbrough, 1856-1930

Edward Wilmot Blyden, born in St. Thomas in what was then the Danish Virgin Islands, immigrated to Liberia in 1851. He eventually became president of Liberia College. Blyden was convinced that the only way his people could gain the world's respect was by building progressive new "empires" in Africa. However, his work on behalf of the American Colonization Society put him at odds with some emigrationists as well as those African Americans who believed their people should pursue a policy of assimilation.

Sierra Leone and Liberia; Their Origin, Work and Destiny; A Lecture Delivered in the Court Hall at Freetown, Sierra Leone, April 22, 1884 by Blyden, Edward Wilmot

By the 1890s, Henry McNeal Turner had become the most outspoken African-American advocate of emigration. Turner's "Back to Africa" message was well received by many poor Southern farmers. They often endured great hardships in their efforts to find passage to Liberia. In 1876, Turner came under heavy criticism when he became vice president of the ACS. He traveled to Africa four times during the 1890s.

Despite these various efforts, emigration and colonization had always met with strong opposition from the black community. The Negro Convention movement, black America's most important arena for political expression and protest during the nineteenth century, was a direct response to the formation of the American Colonization Society and Liberian colonization. In 1818, three thousand free African Americans answered a call from James Forten and the Bishop of the African Methodist Episcopal Church, Richard Allen, to convene in Philadelphia. The assembly denounced the ACS's colonization scheme as an "outrage having no other object in view than the slaveholding interests of the country." They expressed the idea that the United States was their home, and though they recognized the inequalities they faced, they maintained that:

if the plan of colonizing is intended for our benefit, and those who now promote it will never seek our injury, we humbly and respectfully urge, that it is not asked for by us: nor will it be required by any circumstances, in our present or future condition, as long as we shall be permitted to share the protection of the excellent laws and just government which we now enjoy, in common with every individual of the community.

Individual African Americans also noted their views on the subject. In 1834 Peter Williams, an Episcopal priest in New York City, objected to the idea that African Americans were best suited to colonization in Africa. "We are NATIVES of this country," he asserted, and "ask only to be treated as well as FOREIGNERS . . . we ask only to share equal privileges with those who come from distant lands, to enjoy the fruits of our labor. Let these modest requests be granted, and we need not to go to Africa nor anywhere else to be improved and happy."