The third debate posted a Nielsen 71.6 million TV viewers across 12 TV networks -- up slightly from 66.5 million in the second debate and down from 84.0 million in the first debate.
Fox News Channel scored the highest results with 11.26 million viewers. ABC was next with 10.96 million, followed by NBC at 10.39 million, CBS with 10.12 million, CNN at 8.68 million, and MSNBC with 5.5 million.
The next four networks were Univision with 2.38 million, Telemundo with 1.48 million, Fox Business Network with 714,000 and CNBC with 559,000.
Among key 25-54 TV news viewers, NBC ranked first with 4.47 million viewers, followed by ABC at 4.37 million, CBS with 3.70 million, Fox News at 3.47 million, CNN with 3.45 million, ABC at 3.31 million, CBS with 2.69 million and MSNBC at 1.79 million.
Top networks for younger viewers 18-34 were NBC with 1.69 million; CNN with 1.64 million; ABC with 1.5 million; CBS with 1.3 million; Fox News Channel with 1.12 million; and Fox with 1.06 million.
Nielsen also says there were 53.2 million social media interactions across Facebook and Twitter from 16.9 million people in the U.S.
Samba TV estimates that 22% of TV viewers did not watch the first two debates, and that 41% of those who watched the third debate watched both previous debates.
In addition, 54% of those who watched third debate watched the second, and 24% of those who watched the latest debate watched the first -- but not the second.