What are the differences/connections between the Churches of Christ and the Congregational Churches?

I have done a fair amount of research but am still very confused about the difference between the two, the Churches of Christ and the Congregational Churches. I know of the United Church and Church of Jesus Christ of Latter-Day Saints, but that is not what I am referring to with the Churches of Christ. Are they the same thing? Are they different? In what way are they different? If anyone has any knowledge regarding this, please share. Thank you very much!