The Internet Crime Complaint Center received more than 310,000 complaints last year, representing a 3.4 percent spike over the previous year, according to the entity's annual report (PDF).
Complainants reported more than $485 million in losses, many related to identity theft, advance-fee schemes and ruses in which victims are targeted via email by someone posing as the FBI.
More than 14,000 people reported being conned by the latter, resulting in losses of more than $3.5 million.
The IC3, a partnership of the FBI, National White Collar Crimes Center and Bureau of Justice Assistance, advised users to avoid opening unsolicited emails and to be wary of individuals who only accept cash or request payment up front.
Alaska, the District of Columbia and New Jersey were the source of the most complaints on a per-captia basis.