The first presidential debate of the 2020 election season delivered huge numbers. The program delivered 73.132 million total viewers, and 48.581 million households across 16 different networks, making it the second-most watched debate in U.S. history trailing only 2016's first contest (84.011 million). People over the age of 55 accounted for the majority of the viewership with 40.496 million in that demographic tuning in, equivalent to a 42.7 rating. Also of note, there were 20.292 million people aged 35-54 (25.5 rating), 8.42 million aged 18-34 (12.0), and 3.924 million people below the age of 18.
Fox News Channel led the networks across the board, including in the key adults 25-54 demo (4.39 rating), the 18-49 demo (3.36), and total viewers (17.812 million). The network also scored a dominating 10.94 rating in people over 50 and a 2.57 in adults 18-34. ABC's coverage was the closest competition, pulling a 4.0 in 25-54, a 3.2 in 18-49, a 2.2 in 18-34, and 12.62 million viewers.
The big four broadcast nets - NBC, ABC, CBS, and FOX - delivered a cumulative 8.9 adults 18-49 rating, an 11.2 adults 25-54 rating, and 34.101 million viewers. The three major cable news nets - FOX News, CNN, and MSNBC - summed to a 6.71 P18-49 rating, an 8.73 P25-54 rating, and 33.288 million viewers. Elsewhere, Spanish-language nets Univision & Telemundo totaled 2.8 million viewers, Fox Business had 758,000, and WGN America logged 123,000. Viewing on Vice, Newsmax, and Newsy accounted for an additional ~300K viewers.
There is some discrepancy about how many viewers watched on PBS. AdWeek reported the number at 2.7 million though I think that's a total rather than an average. The 15 ad-supported nets accounted for 71.5 million viewers of the 73.1 million total, so it looks like PBS averaged approximately 1.6 million viewers. In looking at data from Programming Insider, the PBS primetime average for the night was about 1.56 million (and a 0.23 rating among A18-49) so that tracks.
Cumulatively, the debate drew approximately a 16.8 adults 18-49 rating, and a 21.0 adults 25-54 rating.
Elsewhere on the night, the CW delivered 303,000 viewers for 'Tell Me a Story,' MTV's 'Teen Mom II' had 682,000 (0.55 in W18-49/0.44 in F12-34), and Comedy Central's 'Tosh.0' had 332,000.
In baseball, coverage of the 'MLB Wildcard' games has been strong. ESPN's Yankees/Indians game notched a 1.02 men 18-49 rating with 2.593 million viewers, and White Sox/Athletics pulled a 0.35 with 953,000 on that same net. TBS also had a game, Blue Jays/Rays, which managed 0.36 with 803,000.