This is picture of the vine which is not hairy or attached to a tree.

Another pic of the vine up close.

Another pic of the leaves

It's not poison ivy. I think it's ampelopsis, and you can tell by the size of the vine that it's, well, let's say "robust". Yes, it can take over your yard. Look at the picture on the linked page, then do a google search on it. Then you'll probably start digging it up.

Here is a link that might be useful: check this picture & see what you think

lisanti07028, thank you for helping me identify this vine. I'm glad to know that it's not poison ivy. Now I just have to work hard on getting rid of it.

Thanks again.

One hyphenated word - Round-Up. Cut the vine to the ground wherever there is a main stem and put a drop or two of full-strength RU on the cut surface, making sure it covers the whole surface out to the bark. A DROP.OR TWO. No need to spray the whole vine, which I assume you will be putting into the garbage. You can pull up the seedlings, but the parent vines are a pain to get up, hence the Round-Up.
If you are totally opposed to Round-Up, as some people are, you are going to have to keep chopping it down as it starts to regrow, which it will.
Either way, good luck.

Sorry about all the art, just wanted to show you a photo of the real poison ivy/oak.

Here is a link that might be useful: Plant pic