By Tim Baysinger

(Reuters) - The 2016 election cycle had been a ratings boon for U.S. cable news networks, and Tuesday’s stunning U.S. presidential election victory by Republican Donald Trump was no different.

Time Warner Inc’s CNN led all U.S. TV networks in primetime coverage with 13.3 million viewers, the most-watched Election Night coverage in U.S. cable news history, according to Nielsen data. 21st Century Fox's Fox News came in second with 12.1 million viewers, and Comcast Corp's MSNBC was far behind with just under 6 million.

Among adults aged 25 to 54, the demographic most important to advertisers who buy time on news programs, CNN was first as well with 6.7 million viewers. Fox News was second with 4.6 million and MSNBC drew 2.4 million in the demographic. All three posted gains from four years ago.

With many states too close to call, the race was not called for Trump until around 3 a.m. (0800 GMT) on the East Coast. Fox News led cable news with 9.8 million viewers watching between 2 a.m. and 3 a.m. (0700 and 0800 GMT), with CNN bringing in 6.5 million and 2.9 million watching on MSNBC.

Fox News also led all cable networks with their full coverage from 7 p.m. to 3 a.m. (0000 to 0800), with 12.2 million, a network high for an election night. CNN pulled in 11.2 million for the whole night, but topped Fox News in the news demographic with 5.6 million to Fox News’ 4.8 million. MSNBC brought up the rear with 5.2 million and 2.1 million in the demographic.

NBC led all the broadcast networks with 11.2 million viewers, with ABC finishing with 9.2 million and CBS pulling in 8.1 million. Fox averaged around 4 million for its two-hour coverage from 8-10 p.m.

Across 13 U.S. TV networks, election night coverage was watched by 71.42 million viewers, just behind the U.S. record of 71.47 million that watched in 2008.

(Reporting by Tim Baysinger in New York; Editing by Jonathan Oatis)