Are you saying that you had wasps IN your house....or around the outside? I'm kind of confused.

Wasps often build their nests where the environment seems safe and suitable. They've learned to take advantage of our porch overhangs, protected eaves, etc. If they discover an avenue into an attic, etc., all the better (for them).

Whether wasps will return to the same nesting site or not depends on many factors. As a rule Yellow Jackets will not nest in the same place two years in a row, but the paper wasps will (I have these nests in my garden shed every year), but that does not mean that a Yellow Jacket queen from someplace else would not decide that you have an excellent nest site. Which wasp did you have?

I have no idea what kind of wasp I had. They were large fellas. Sorry for the confusion. The wasps WERE in the attic but the vent is closed to them now. They were NOT in the house this spring - just around the outside and on the deck. They really were persistent for a couple of weeks, like it was their mission to get into this house. I really thought there was some "homesteading transference" from the dead wasps that used to be in the attic to these very alive guys this summer.

Probably a stupid question. Does the queen survive a northern winter? Could she have led them back here?

Nope...I think their presence simply indicates that they have found the location suitable. There's obviously a food source somewhere, protection, nest building materials, etc.

On a side note, there were some very persistent paper wasps living somewhere near our back patio one year. A couple of them would land on the pages of my book (while I was reading) to munch off minute mouthfulls of paper to take back to the nest. It creeped my husband out, but I though it was fascinating to get such a close-up glimpse of these creatures.