When the Fairfax County Animal Shelter was built in the early 1970s, it was intended to be a dog pound to handle stray and homeless dogs. Renovated in the mid-1980s, it increased the number of kennels from 48 to 72 to better care for dogs in isolation and quarantine.

But as time went on and the county’s human population skyrocketed to more than 1 million, the pet population also increased. Eventually, the shelter began taking in more cats than dogs.

And as area developers constructed higher-density homes — such as townhouses, apartments and condos — more people began keeping smaller pets, such as ferrets, snakes, hamsters, guinea pigs, gerbils, rats, iguanas, rabbits and birds. And although it was never designed to house such exotic creatures, the shelter began receiving them.

Soon, the small, 15,000-square-foot facility became cramped, crowded and outdated. But employees and animals alike had to make do with what little space they had.

By fall 2006, for example, one animal-control officer worked next to exposed electrical circuitry at a desk literally inside a closet. Wildlife was stored beneath the printer in the main office and small animals were housed in the same room with their predators.

Lining a hallway were ferrets, rabbits, an iguana and, sometimes, birds and guinea pigs. Making matters worse, the air-ventilation system was inadequate to prevent airborne diseases from spreading from sick to healthy animals.

Meanwhile, then-Shelter Director Karen Diviney had been beseeching the county for help — and, finally, it came. In November 2006, residents passed a public-safety bond that included $17 million for a much-needed shelter renovation and expansion. That started the wheels turning and, in 2011, ground was broken for the shelter’s renewal.

It’s now nearly doubled in size, to 29,000 square feet, and boasts separate lobbies for adoption and animal receiving, new animal-holding spaces, a small-animal room, play yards, training rooms, a new air-ventilation system, more space for employees, a veterinary suite, visitation areas for adopters to meet pets, plus additional parking.

After Saturday’s ribbon-cutting for the new improvements, shelter volunteer Rebecca Walter showed visitors around the new room solely for small animals such as bunnies and ferrets. “Before the renovation, the room was packed with animals and they were in smaller cages,” she said. “We make sure they get socialized and have some ‘out time.’ And now we can have multiple animals out at once, for visits from the public, because there’s also a separate area behind a barrier for that.”

Centreville’s Carol and Tom Starr adopted a dog from the shelter six months ago and, on Saturday, he came to the shelter with them while they picked out a buddy for him, a mixed fox hound puppy.

“This is our fourth dog we’ve adopted from the shelter,” said Carol Starr, of the Confederate Ridge community. “The first two lived their whole lives into their teens.” Now, she’s one of the shelter’s biggest cheerleaders.

“There are so many wonderful dogs that need homes, and people can just come right here and get them,” she said. “This shelter, the employees and the volunteers are wonderful.”

The Fairfax County Animal Shelter is at 4500 West Ox Road and is open Tuesday through Friday, noon to 7 p.m., and Saturday, 10 a.m. to 5 p.m. For more information, go to http://www.fairfaxcounty.gov/animalshelter.