The mission: To care for animals and protect them from cruelty.
Why it stands out: The number is staggering—76,000 animals (including injured wildlife and victims of natural disasters, puppy mills, research labs, and the exotic-pet trade) have their lives improved by the Humane Society every year. The largest animal-protection organization in the country and its affiliates also offer a wide range of vital services, such as free spaying-and-neutering clinics, medical treatment, and rescue and emergency care. Case in point: After Hurricane Irene, in 2011, the society opened emergency shelters in North Carolina and Vermont to care for displaced pets and handed out pet food for animals affected by the disaster.
Your money at work: A $100 donation provides an abused cat or dog with medical care and shelter while it awaits adoption.