Abraham Lincoln wanted to return all freed slaves to Africa, so why didn't that happen?

Because Lincoln was assassinated.

Also how do you get 3+ million (former) slaves across the ocean in the mid 1800's?? This would be a huge undertaking in modern times. 150 years ago in the days of wooden sailing ships - near impossible.

And what do you do if they don't want to go?? By this time they were pretty Americanized and Africa/Liberia would have been a totally alien country.

Because that was impossible. Lincoln supported that at one point - by the end of his life (which he did not see coming, of course), Lincoln had publicly advocated for giving freed slaves the right to vote (a concept which is pretty much incompatible with a policy of transportation).

In fact, Lincoln's so-called "last speech," in which he advocated giving freed slaves the vote, was what finally caused John Wilkes Booth to decide on assassinating Lincoln.

You're a bit confused. Liberia was founded in the 1820s during the presidency of James Monroe, who the Liberians capital of Monrovia is named for.

Colonization, the idea that freed slaves should be returned to Africa, enjoyed a brief heyday in the US in he 1820s and 30s. But it died out quickly after that. The major reason is that African-Americans were mostly opposed to it. Despite a large upsurge in slave imports in the twenty years before the end of the American slave trade in 1808, most African Americans at this time had never been to Africa. They were born and raised in the US. There were some African-Americans who were interested in the idea of emigrating to Africa, but the majority of African-Americans, especially free people of color, had absolutely no interest in abandoning their own country to travel to a continent that they had no experience with.

Lincoln had always supported colonization as a voluntary thing. He felt that freed slaves would want to emigrate to someplace and start their own society rather than trying to make it in the racist world of 19th century America. When he realized that there was virtually no support for colonization among African Americans themselves he abandoned the idea.

The slaves in the 1860's only knew about the U.S., they only heard tales about Africa.

Fail on all counts. Learn to read books instead of graffiti.

For one thing, the blacks born in America might not have wanted to go back to where they never lived.

because Lincoln never cared about the Slaves Just did Not want them in his state

once he won the war and saved his job the African american became Unimportant which is Typical of any Racist

it's very clever

No he did not. Fallacy. Fail.