Well I know where a couple are from the early folks here in my area.
My plan is to wait till next year and get my start. It's not exactly a good growing time this time of year so might as well leave them be where they are healthy for now.
I intended to do it this year, but it's not real close to the house and I didn't get a chance at the right time. I checked too early a couple times on one of them.
There are hops out an old gravel road near an old Chinese cemetery in the middle of nowhere but the trick is you have to wait till they grow enough to see them come up through the blackberries! I made it early and didn't make it when they were at full growth.
I haven't seen them in over a year, but they've been there long enough that I'm sure they'll still be there next year.
My brother owns a good chunk of one of the bigger homesteads around here. His place is right near where the original house would have been. He says he's got hops out there also.