I just built a pond (several weeks ago) - it's about 350 gallons. I picked up a green frog from a local nursery (netted it - it got out of the bag in the car... different subject).
He called, and called, and a couple of days later, a female showed up. A couple of days after that, lots of eggs showed up (I now have several hundred tadpoles in there). They both hung around for several days, and then both disappeared. It's been REALLY rainy. Is it possible that they just wandered off? There is a large pond about 200 yards away, and a river about 1000 yards away.
Or... is it more likely that the orange cat that likes to hang around the pond got them?
bob

Green frogs (and other frogs) absolutely will wander off. When it's rainy, it provides the perfect opportunity for them to go on an adventure. They naturally want to see what other water sources are around so they can try to find something better and also so they can lay eggs around various places. My green frogs come and go. They travel between six of my ponds but I've also found them at ponds a quarter mile away that never had green frogs before. I think mine traveled that far over almost 10 years. So, your frogs could have wandered off (at least they left the next generation). But, they also could have been killed by a predator. I have one cat who kills mine on occasion, and the standard pond predators (herons, raccoons, etc.) will also eat frogs. I hope yours just hopped off!

I have a new green frog. He's a little smaller, and doesn't have the voice of the original. Just showed up yesterday. So obviously there ARE green frogs in the ponds around the neighborhood. I noticed the original one seemed a little antsy the day before he left - spent most of the day a couple of feet from the pond instead of inside, or on the coping around it, where he had always been before. So maybe he just got a wanderlust. Maybe he wanted to be a big frog in a big pond instead of a small pond. The tadpoles are doing fine, though :)
Thanks for answering! Off to finish that waterfall today, I hope...

bob (In Northern Virginia) :)

I have some frogs that are living in my pond some. I would include a picture of them sitting on some water lettuce if I could figure out how.

I have quite a bit of experience with frog related issues:

As for the Northern Green Frog, it is likely that the male frogs will remain in your pond indefinitely, as they are territorial; as for the females, they seem to wander off and I do not know if they are (as) territorial.

I had a 6 x 11, well planted, garden pond - the females wandered off and the males stayed - one female stayed a long time, though.

When it rains, they migrate.

If you have a large enough pond, hopefully they will all stay. If you have them in your area, I would not worry about, especially if you get eggs, which will ensure enough will mature and stay.

I still didn't build my pond - i think this week - a 24 x 35