In short, yes; in full, not exactly! However, there's a good bit of debate about the word 'reparations' and the satisfaction with it. For example, many everyday people see reparations as a check you get in the mail with "Sorry" as the byline when there can be many more forms of reparations than this. Reparations are a question that go far beyond monetary reimbursement and whenever monetary reimbursement is provided it is more symbolic of apology, acceptance of guilt, etc. than an effort to buy blood for money.
For example, the United States paid reparations to Japanese-Americans interneted by the government during WWII. The American Civil Liberties Act of 88' awarded $20K to each living detainee. Again, understand that this was literally a reward giving to those that this actually happened to, not simply relatives of the individuals.
When it comes to Native Americans the issue becomes a little bit more tricky, partially because Native Americans generally don't seem as interested in a big paper check as they do the restoration of their dignity, culture, and land. Native Americans haven't really gotten much in the way of lump sums distributed upon the sudden realisation of injustices done to them but some people might see the parceling of land for reservations as reparations. In addition the individual lawsuits won by the Bureau of Indian Affairs against the government for certain plots of land for reclaimation are seen as reparations of a kind though it must be noted that many of these suits are lost because proof of 'ownership' must be presented. There are also suits wherein Congress acknowledges individual tribes and things of that nature. You've also got instances where the government awards Native Americans a large lump sum but these are usually as a response to lawsuits filed on behalf of Native Americans against the government for mismanagement/mishandling of Indian Affairs. In an example of this last point, a settlement of over $3 billion was reached in 2012 on this exact issue.
As far as reparations for slavery, the answer is no. Reparations, including the "20/40 acres and a mule" urban legend, have not been made to descendants of victims of slavery. Public apologies, sure, but no tangible reparations.
It should be noted here that there are many arguments regarding reparations. For example, how to reimburse an individual for their grandfather's slavery. How would you put a number on that? Would you pay them the grandfather's worth at the time? Would you try to estimate the effect that slavery had on the family (a legitimately impossible task) and then write a check for that much? In the case of Native Americans, would you force everyone out of the country except for those who can provide a direct native heritage? This slows down the process of reparations as well as the debate concerning them considerably.
There are also a good deal of opposition points against reparations, particularly against those concerning slavery. The difficulty in determining the exact amount of reparations, the ingrained ideas of what reparations "should be" (i.e. the 40 acres/mule myth), the effects of almost instantly changing the economic landscape of America by enriching one race of people, the potential conflict reparations could spark between races (i.e. Chinese-Americans resenting African-Americans for being paid for their great-great--great-grandparent's work but the Chinese-American not being reimbursed or acknowledged for their grandfather/great-grandfather's arguable near-slavery on the railroads, Irish-Americans, Muslim-Americans, etc.), the legislative precedence that writing checks to people four or five generations after something was done and when the people receive the funds were not even alive, etc.
In summary, yes, some reparations have been paid to some descendents of those wronged by the United States government but certainly not all of them. The issue of paying descendents for crimes against their ancestors is a difficult question and not one that the government or the people have had an easy time dealing with. ===== == ========== ============= ========== ========== ============= =====
Sources: African Americans and Movements for Reparations: Past, Present, and Future
The Great Confusion in Indian Affairs: Native Americans and Whites in the Progressive Era
Tribes, Treaties, and Constitutional Tribulations
Prisoners Without Trial: Japanese Americans in World War II (Hill and Wang Critical Issues)