ABC News reported the fake order was allegedly made by a local company.
"They placed a fake order on us and they didn't know that it hurt our feelings a lot," girl scout Erin Donnelly, 8, said.
The girls said they had already put the order through and were therefore desperate to sell the boxes of cookies to help pay for their summer camp and donate to the homeless shelter.
Determined to raise the money, they held an emergency sale in Portland on Saturday and as news spread of the hoax, hundreds of people lined up to support the girls, Fox News reported.
As of Saturday night, 3,000 boxes had been sold and more sales were coming in from across the United States via an email order system.
“I’ve been a girl scout for 23 years,” girl scout spokeswoman Sarah Miller told KATU.
“I’ve never seen anything like this.”
She said she expected a few people to buy some boxes of leftover cookies to support the girls.
“Never in my wildest dreams did I imagine this many.”