Justice Rescue posted the reward on Wednesday morning. The money is for whoever can provide information leading to the arrest and conviction in the case.
Justice Rescue is working alongside the Delaware County SPCA's humane investigator in order to find the owner of "Curious George."
The group says callers must mention they saw this poster to claim the reward.
Tipsters can call the Delaware County SPCA or email Justice Rescue at email@example.com at 610-566-1370.
Earlier Wednesday, the Delaware County SPCA said George was resting and keeping warm in his new surroundings.
In an update provided on Wednesday morning, the SPCA said the dog was "staying warm in his sweat suit on his memory foam bed, eating every two hours."
They went on to say he was "wagging at every person he meets, like usual!"
The SPCA said George's condition is no accident, however, and authorities are still looking for the person who starved the dog. They called it the "worst act of cruelty and deprivation we've seen."
Curious George was found on Monday by a Good Samaritan, staggering along the 1600 block of Naamens Creek Road near Boothwyn.
Investigators say someone deliberately did this to George. Dayna Villa of the Delaware County SPCA says a stray left on his own would have found more nutrition eating out of garbage cans.
Authorities say the dog, which should weight 60-70 pounds, weighs just 35 pounds. Vets say they will know if he will make it through his hardships in the next five to seven days.
If you would like to make a donation to help pay for George's care, you can make that donation through the Delaware County SPCA's website.