Anywhere there are bees you are likely to catch swarms.
I have old equipment that I'm converting into traps and have a number of other beekeepers collaborating with me on placement of traps at a variety of locations. I'm specifically looking for feral colonies with natural mite resistance, but I catch a lot of managed bees too.
I'd be willing to help you with swarm traps if you're willing to allow me access to the swarms you catch in order to assess them for mite resistance and potentially raise a few queens off of them (or trading colonies with you if you have no interest in treatment-free management).
I'm in Cottage Grove but also keep bees at several locations in the Deerfield area.
Joe