Grim Dawns Bounties by Faction

This Will be repeated in the page that the link will take you but i think it bears being repeated.

• Bounties are unguided, with minimal instructions and no quest markers on the mini-map.
  
• There is a maximum of five bounties per faction per game session.
  
• players can have one bounty from each faction active at any given time.
  
• Bounties can still be undertaken after reaching maximum reputation. For extra XP and Money.
  
• In addition to the reputation reward for completing a bounty, killing bosses and heroes can grant bonus reputation.
  
• Killing an enemy prior to accepting a bounty on them does not complete the bounty, however you can be offered bounties for enemies already dead in that session of the game.
  
• Bounty reputation rewards are doubled if a character has a mandate, but the quest reward window will still show the 'normal' value.

Step 1) go here http://grimdawn.wikia.com/wiki/Bounty

Step 2) find the faction the the bounty is for and then look in that Factions Bounty List

Step 3) go to that location that the bounty is tied to and look for that monster.

Remember: Killing an enemy prior to accepting a bounty on them does not complete the bounty and if you recive the same bounty you must exit to the main menu and re-enter the session on that character to complete it.

On a side note to increase your reputation, by killing monsters, with a friendly or hostile faction the enemy must be within 10 levels of your current level.

Another note if the bounty requires you to get a Ancient Heart, Blood of Ch'thon, Royal Jelly, or a Tainted Brain Matter you will be grinding boss and hero spawns until you get said items and for best results the spawn must be with in five levels of your current level.

Ancient Heart: can be obtained from Hero and up Beasts, Beastkin and Eldritch creatures.
Blood of Ch'thon: can be looted from Ch'thonic and Bloodsworn Heroes, Bosses and Uniques.
Tainted Brain Matter: can be looted from Aetherials and Aether Corruption Heroes, Bosses and Uniques.
Royal Jelly: can be looted from the Unique bosses in the Stirring Hive and Swarming Hive, or from Wasp Nest containers or It can be found in great quantity in the Staunton Mine.

Unless you have said item(s) stockpiled then you just need to get the Required item out of your stash or go grind for it.