Charles Diggs, 36, of Roselle, New Jersey, was indicted by a state grand jury on Thursday.
Local authorities began the investigation after a tip from the National Center for Missing and Exploited Children about child porn being posted to a Twitter account.
The investigation led back to Diggs and, authorities say, they found more than 325,000 files of child pornography, including more than 14,000 videos.
Many of the files depicted the rape of "very young children," investigators said.
"Diggs allegedly had the most child pornography ever found in a state investigation - more than four times the prior record," said Attorney Christopher General Porrino in a statement. "It's heartbreaking to think of the many thousands of children who were raped and robbed of their innocence to create the images and videos he allegedly possessed."
This comes just weeks after the conclusion of "Operation Statewide," which resulted in the arrests of 40 child porn suspects.
Anyone with information about possible child porn, or the exploitation or sexual abuse of children, is asked to contact the New Jersey Internet Crimes Against Children Task Force Tipline at 888-648-6007.