Statistics published on Twitter's @gov feed revealed that 7.2 million messages were posted during Tuesday night's (October 16) debate at Hofstra University in New York.
Twitter traffic during the debate peaked at 109,560 tweets per minute during an immigration question posed to Romney and his response.
The debate, which included numerous heated exchanges between Obama and Romney, took a town hall meeting format where undecided 'swing voters' posed questions on areas of domestic and foreign policy.
The top five areas of policy mentioned in tweets relating to the debate were the economy (28%), taxes (17%), foreign policy (16%), energy and the environment (13%) and immigration (8%).
The candidates' first presidential debate broke a Twitter record for US political events earlier in the month.
3.5 million tweets were sent during last week's vice-presidential debate between incumbent Joe Biden and challenger Paul Ryan.