An indoor only cat is almost certainly very close at hand. Look in, behind and under any place the cat may be hiding, starting right from the exit point — in dense plantings, under a porch, house crawl space, storm drains. (A cat can crawl through an incredibly small slot when it needs to.) And don’t neglect to look up, even if the cat has been declawed.
When an outdoor-access cat disappears
When an outdoor-access cat disappears, it means that something has happened to the cat. That is because cats are territorial and do not just run away from home. They find themselves trapped, they get driven away from their territory, they become ill or injured and creep away to a quiet dark place. Thoroughly search the surrounding property and go door-to-door asking neighbors for permission to look on their property. Most people will gladly cooperate. Look around and try to imagine what could have happened to account for the disappearance. Have any neighbors recently moved, gone on vacation, or is their construction? If you have recently moved, check your old neighborhood and talk with people there and post flyers. When an owner moves their cat to a new home, lets the cat outside, it often leaves in order to find its way back to its old, established territory.
Search at Dawn and Dusk
Many cats will venture out of hiding between 1-5 AM because they feel safer in the dark. Sit quietly in your yard and call your cat softly. Jingle its favorite toy or shake a box of dry cat food, open a can of food. Softly call the cat while looking. Remember the cat may not respond — it’s terrified of everything, including you — but it may give a very faint reply. Use a flashlight to search all the areas you explored earlier.
Contact All Area Shelters
While a shelter will not pick-up a cat it is possible that someone will turn your cat in. However, please keep in mind that this could take weeks or months because someone is not likely to help a cat until it appears lost (skinny, dirty) which can take quite a while.
Ask the children in your neighborhood to help find the cat — they network well and know the “hiding places” in your neighborhood better than the adults do. Question others, such as dog walkers, joggers, postal carriers and ask them to keep an eye out for your cat
Post “Lost Cat” flyers in your neighborhood, pet supply stores, veterinary clinics. Place an ad in the paper. Add a lost cat post on this website. If you’re on social media be sure to post there too. Offer a reward if possible. Caution: leave out one of your cats identifying characteristics so you can verify the honesty of any person claiming to have found your cat.
Set a Humane Trap
There are many reasons why your cat may be close to home, but too afraid to make himself known. This is especially true of indoor only cats. Setting a humane trap may do the trick! This trap is a wire cage with a trip mechanism that closes a door when the cat enters the trap to get food. Once shut, the cat cannot get loose. Its important to monitor these traps regularly (e.g., every or hour or so). Do not leave them open overnight or throughout the day. A scared cat can injure himself in a trap if left unattended for too long. Traps are available at most animal shelters, some vet offices, as well as pet stores and hardware stores. You may also trap other critters (e.g., another cat, raccoons, opossums etc). Don’t worry. Just open the trap up and let it scurry away.
Don’t Give Up.
Many pets are found weeks or months after they disappear. Keep looking in those same old spots, calling and listening. Try new spots, enlarge your search-area. Your pet has to be somewhere, so don’t give up too soon.
These tips were excerpted from this post http://www.spcanova.org/lost/lostcats.php
The tips on spcanova.org include putting food, water, bedding and litter box outside. Please take into consideration what other animals this may attract. Some areas regularly have visits from squirrels, raccoons, opossum and other small wildlife. Other areas also have coyote and other larger animals, from whom you want to exercise caution in the everyday care of your cats and other domestic animals.