The `Killers` actress has pledged the enormous sum to the city as part of a new initiative to get animals spayed and neutered in honour of her late brother Jason Heigl - who died in a car accident in 1986 when he was a high school student.
Katherine told `Access Hollywood`: "I said to my mother, `I think it`s a really grace-filled way to honour him.` My mother began the foundation in his name as a way of creating a legacy for this child of hers that didn`t live long enough to do that himself and he also happened to be a real advocate for animals and children and the repressed so it works out beautifully.
"It`ll never change how this day feels to us come September 23 every year. It has a significance now, of beauty, a grace to it, that we are grateful for."
The Jason Debus Heigl Foundation aims to stop the pet population crisis in the area with neutering schemes, but also through its support of training and obedience programs, rescue organisations, `no kill shelters`, pet adoption schemes and programmes which help move homeless animals away from shelters which intend to put them down.
Katherine has always been known for her love of animals, and her own dogs play a huge part in her family life with husband Josh Kelley and their 21-month-old adopted daughter Naleigh.
She said: "Mostly they just lick Naleigh`s face. The bigger ones she doesn`t like because they lick her too much and she can`t get away from them.
"My thing with her is you don`t ever want to get aggressive towards the animals; she`s in a hitting phase - like, she`ll take wooden spoons and hit me with them, or hit whoever, hit a dog - and we`re really trying to teach her, `No! That`s not acceptable. You can`t hit the dogs, because that`s when something bad will happen, that`s when they react. So we`re teaching her you know, `Gentle pets, nice dog, good boy,` and she`s really great about it."