Oldham is experiencing a "cat crisis" with the largest number of emergency call-outs.
Local RSPCA veterinary director Caroline Allen said many of the injured or neglected cats brought in by their inspectors were strays:
" figures show that Oldham is the area with the highest concentration of cat-related incidents per person. Sadly, we will never truly know why there is such a big issue here.
"Particularly in the summer months, animal charities are inundated with kittens with no one to care for them, many have been born in a garden shed to a cat that has not been neutered. Sadly others can be deliberately dumped by owners who did not expect their cats to give birth."
The RSPCA said it was being inundated with calls to deal with neglected, maltreated, injured and stray cats in Greater Manchester. It said, per 100,000 of population, it had more calls in Oldham (501) and Bradford, West Yorkshire (473) than anywhere else in 2015.
She said animal charities were struggling to keep up with the demand for space in their rescue centres and some had resorted to re-homing cats in "costly private boarding".
For details of how to help the RSPCA log onto http://www.rspca-buryoldham.org.uk/