A combined audience of 30.6million people watched the live coverage between 10am and 6pm (EST) across 12 broadcast and cable networks, according to official Nielsen figures.
The figure is 11m more than the audience that watched Mr Obama’s second inauguration four years ago when 20.6m in 2013.
Donald Trump is sworn in as the 45th US President
The audience for Trump was bigger than either of his Republican predecessors George Bush and George W Bush.
Bill Clinton’s inauguration in 1993 was watched by a TV audience of 29.7m.
Donald Trump becomes 45th U.S. PRESIDENT
Fri, January 20, 2017
The inauguration of Donald Trump as the 45th President of the United States will mark the commencement of the four-year term of Donald Trump as President and Mike Pence as Vice President. A public ceremony will be held on Friday, January 20, 2017, on the West Front of the United States Capitol Building in Washington, D.C.
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US President Donald Trump points to the stands as he walks with his wife Melania during the Inaugural Parade.
Mr Trump’s audience is the fifth biggest TV audience ever for an presidential inauguration.
The largest ever recorded was for Ronald Reagan’s ceremony in 1981 which was watched by 41.8m even
The audience for Mr Obama’s first inauguration in 2009 gained the highest TV audience in recent years with 37.7m.
Donald Trump during his inauguration as he is sworn in
Other notable inaugurations include Jimmy Carter in 1977 which drew an audience of 34.1m and Richard Nixon in 1973 which pulled in 33m.
Mr Trump fully aware of the importance of TV ratings, having had a previous career as a reality TV star.
Earlier this month he launched an attack on the new version of The Apprentice where he serves as an executive producer because the ratings of the premiere edition of the new series fell short of the standards set by the programme when Mr Trump appeared as the host.
Crowds watch on as Donald Trump is sworn in as the US President
The then president-elect tweeted: “Wow, the ratings are in and Arnold Schwarzenegger got ‘swamped’ (or destroyed) by comparison to the ratings machine, DJT.
“So much for being a movie star — and that was season 1 compared to season 14. Now compare him to my season 1.”