Unless you used Kill Warrant scanner that shows galaxy-wide bounties, then the bounty you collect is for the current system only. Go to the system map and check the outposts and stations. You'll see which faction they belong to in the info.
I do have one problem with this, though, myself. I did some bounty hunting
somewhere and forgot to redeem to bounty. Now I forgot which system it was and the info in the transactions panel only shows the name of the faction, which has no hint of what system it resides in.