Thieves in Philadelphia broke into a truck filled with $750,000 (£598,000) worth of dimes.
The suspects made off with a chunk of the cargo - leaving 10-cent coins scattered around a Philadelphia car park.
Police say the thieves apparently fled with at least $100,000 (£80,000).
It's not yet known how they carted off over one million coins.
The theft was reported around 6am on Thursday.
The driver had picked up the coins from the Philadelphia Mint on Wednesday, and was planning to transport them to Florida on Thursday.
It's not clear how many people may have been involved in the theft or if they knew what the truck contained.
Responding police officers found hundreds of dimes scattered all over the parking lot, and authorities were still trying to determine how much money was stolen.
No arrests have so far been made.