Let’s say that the players are on the road or even in a dungeon and they encounter a group of people (other adventurers, prisoners, etc), could a player use their Circles ability to look for someone within the makeup of that group? I would say yes, but the book seems pretty clear it is an in-town ability only. Of course, if they fail, they may find that the person they are looking for has the exact information/thing they need but are their enemy.
If it makes sense to you as the GM, go for it.