Logan Paxton, 4, of North Babylon, observes Hercules, an American...

Logan Paxton, 4, of North Babylon, observes Hercules, an American alligator during the Long Island Pet Expo at the Suffolk County Community College in Brentwood. (March 3, 2012) Credit: Ann Luk

Dogs and cats will fill Polish Hall in Riverhead next Saturday when seven different animal shelters and animal welfare groups come together for their first mass Pet Adoption Expo.

Sponsored by the Animal Rescue Fund of the Hamptons, the expo will bring in animals from the as close as Kent Animal Shelter in Calverton and as far as the Town of Hempstead shelter in Wantagh.

“We picked Riverhead because it was kind of central,” ARF spokeswoman Jamie Berger said, adding that at least 100 dogs and 50 cats would be available for adoption at the event.

The expo is free, but people who adopt a pet will have to pay the costs charged by each of the individual agencies involved, generally from $50 to $200.

The pets will be spayed or neutered, vaccinated and microchipped. Dogs will go to their new homes with a free leash and collar, and cats will get a free cardboard carrier.

The event will be held March 31 from noon to 5 p.m. at the hall, 214 Marcy Ave.

The groups taking part in the adoption program are: Kent Animal Shelter in Calverton, LI Kitties in Speonk, North Fork Animal Welfare League of Southold, SAVES of Greenport, Southampton Animal Shelter Foundation in Hampton Bays, Yorkie 911 in Deer Park and the Town of Hempstead Animal Shelter in Wantagh.