The Hill said the milestone was announced Saturday in an email to Obama's supporters, about a month after the campaign announced it had received donations from 3 million people.
The Obama campaign raked in $181 million in September, a new monthly record for the 2012 campaign, which comes to a close in November.
The ongoing haul was put to use opening nearly 800 campaign field offices in the past three months. The Hill said Republican challenger Mitt Romney opened 295 offices during the same period.
Notable deaths of 2014 [PHOTOS]