Looks like you have a Florida White bunny. Probably either escaped from a hutch or was an Easter bunny that someone dumped.
I suggest you keep him/her in the house. You can use a dog kennel, cage, or playpen for now. Playpens are the best though, since they provide enough space for all their needs while still allowing space for exercise.
Their diet should consist of 1/4 a cup of pellets a day, about a handful of spring mix veggies for breakfast and dinner, and unlimited timothy hay. And of course plenty of fresh water from a bowl.
If you are still unable to get food you can give him some lettuce, bits of grass, herbs, fruits like apple and bananas, just be sure that he's eating. If a rabbit goes without food in it's system for over 12 hours, it'll go into GI stasis and can die within 24 hours. Keep a close eye on him but give him some space to be sure he eats.
Do you plan on keeping him if you can't find his owner? If so, I have lots more information on keeping rabbits. If not though I recommend you check out the House Rabbit Society, you can look for a rescue location near you. I would go with them over any animal shelter because they know how to find good homes with people who know how to properly care for rabbits. They always match the right rabbit with the right owner. If they do not have a location close enough to you, look for animal shelters that take rabbits. Personally, I would look for the requirements needed to adopt a rabbit to be sure they will go to a good home. Or you could rehome him yourself. Just don't post on places like craigslist, where there are lots of scammers.
Hope this helps. If you have any more questions just let me know