Bounties are set tasks. For example, locate and kill a Superunique or Boss monster or complete an event or clear a dungeon and be rewarded with Experience, Gold and possibly a Rift Keystone. You access a Bounty by using the Waypoint map and selecting a waypoint marked with an exclamation mark (!) or Diablo's skull icon (indicating boss or quest boss). ^[1]

There are 25 random bounties per game, 5 per act.
You do not need to complete Campaign mode to access Adventure mode and Bounties.
Rewards for completing Bounties can sometimes be a Rift Keystone Fragment which are used to open Nephalem Rifts. Also experience points and gold and Blood Shards which can be used to Gamble with Kadala.
Bounties are not repeatable in the same game. You need to leave and begin a new game to refresh the bounties available.

List of Bounties in Diablo 3

Act I

Kill	Location
Bellybloat the Scared	Cathedral
Boneslag the Berserker	Halls of Agony
Braluk Grimlow	Cathedral
Butcher	Chamber of Suffering, Halls of Agony
Cadhull the Deathcaller	Southern Highlands
Captain Cage	?
Captain Clegg	The Royal Crypts
Dataminer	?
Fecklar's Ghost	The Festering Woods
Firestarter	Cathedral
Galush Valdant	Festering Woods
Garrach the Afflicted	Halls of Agony
Grimsmack	Festering Woods
Growler	Fields of Misery
Killian Damort	Cathedral
Logrut the Warrior	Southern Highlands
Lord Brone	?
Lorzak the Powerful	?
Mange	The Weeping Hollow
Merrium Skullthorn	Cathedral
Mira Eamon	The Weeping Hollow
Queen Araneae	Chamber of Queen Araneae, Caverns of Araneae
Reggrel the Despised	Northern Highlands
Skeleton King	Crypt of the Skeleton King, The Royal Crypts
Theodyn Deathsinger	Northern Highlands
Clear	Location
Cave of the Moon Clan	Southern Highlands
Southern Highlands	Southern Highlands
Den of the Fallen	The Weeping Hollow
Khazra Den	Fields of Misery
Scavenger's Den	Fields of Misery
Event	Location
A Farm Besieged	Forlorn Farm, Fields of Misery
The Apothecary's Brother	Highlands Cave, Northern Highlands
Crumbling Tower	?
Eternal War	Festering Woods
Last Stand of the Ancients	The Festering Woods
The Matriarch's Bones	Defiled Crypt, Cemetery of the Forsaken
The Precious Ores	?
Cursed Event	Location
The Cursed Bellows	?
The Cursed Chamber of Bone	Cathedral
The Cursed Court	Cathedral
The Cursed Cellar	?
The Cursed Mill	Fields of Misery

Act II

Kill	Location
Balzhak	?
Barty the Minuscule	Stinging Winds
Belialm	Imperial Palace, City of Caldeum
Bonesplinter	Road to Alcarnus
Hellscream	Archives of Zoltun Kulle
Hemit	Howling Plateau
High Cultist Murdos	?
Mage Lord Flaydren	Archives of Zoltun Kulle
Mage Lord Misgen	?
Maghda	Lair of the Witch, Road to Alcarnus
Pazuzu	Desolate Sands
Plagar the Damned	Desolate Sands
Raiha the Vicious	Desolate Sands
Razormouth	Howling Plateau
Rockgut	Unknown Depths, Archives of Zoltun Kulle
Saha the Slasher	?
Sammash	?
Taros the Wild	Howling Plateau
Tomekeeper	Archives of Zoltun Kulle
Torsar	Dahlgur Oasis
Zoltun Kulle	Soulstone Chamber, Archives of Zoltun Kulle
Clear	Location
The Ancient Cave	Dahlgur Oasis
Cave of the Burrowing Horror	Desolate Sands
Mysterious Cave	Dahlgur Oasis
Ruins	Stinging Winds
Sirocco Caverns	Howling Plateau
Vile Cavern	?
Event	Location
Lost Treasure of Kahn Dakab	Tomb of Khan Dakab, Dahlgur Oasis
A Miner's Gold	Howling Plateau
Prisoners of Kamyr	Dahlgur Oasis
Restless Sands	Stinging Winds
Sardar's Treasure	Tomb of Sardar, Dahlgur Oasis
The Shrine of Rakanishu	Dahlgur Oasis
Cursed Event	Location
The Cursed Battlement	Howling Plateau
The Cursed Pit	?
The Cursed Shallows	Flooded Cave, Dahlgur Oasis
The Cursed Spire	?

Act III

Kill	Location
Allucayrd	?
Aloysius the Ghastly	The Keep Depths
Azmodan	Heart of Sin, The Core of Arreat
Bashface the Truncheon	Stoneford
Belagg Pierceflesh	?
Captain Donn Adams	The Keep Depths
Cydaea	Tower of the Cursed
Charuch the Spear	Arreat Crater
Crusher	The Keep Depths
Demonika the Wicke	Tower of the Damned
Emberwing	?
Ganthar the Trickster	Skycrown Battlments, Stonefort
Gholash	Tower of the Damned
Ghom	Larder, The Keep Depths
Gorog the Bruiser	The Core Arreat
Hyrug the Malformed	?
Lummock the Brute	?
Marchocyas	Skycrown Battlements, Stonefort
Mehshak the Abomination	The Battlefields
Obis the Mighty	Skycrown Battlements, Stonefort
Sawtooth	Arreat Crater
Siegebreaker the Assault Beast	Edge of the Abyss, Rakkis Crossing
Snitchley	?
Vicious Gray Turkey	The Keep Depths
Clear	Location
Barracks	The Battlefields
Caverns of Frost	Fields of Slaughter
Cryder's Outpost	?
Forward Barracks	The Battlefields
Icefall Caves	The Bridge of Korsikk
Event	Location
Blaze of Glory	Rakkis Crossing
Blood Ties	?
Forged in Battle	The Keep Depths
Cursed Event	Location
The Cursed Depths	?
The Cursed Garrison	The Battlefields
The Cursed Glacier	The Bridge of Korsikk

Act IV

Kill	Location
The Aspect of Anguish	?
Aspect of Hatred	The Silver Spire
Aspect of Lies	The Silver Spire
Aspect of Pain	Gardens of Hope
Aspect of Sin	The Silver Spire
Diablo	Crystal Arch, The Silver Spirem
Hammermash	Hell Rift
Izual	Great Span, The Silver Spire
Kysindra the Wretched	The Silver Spire
Khatun	?
Koa'Ahn	Gardens of Hope
Oah'Tash	Gardens of Hope
Pyres the Damned	?
Rakanoth	Gardens of Hope
Rhau'Kye	The Silver Spire
Slarge the Behemoth	?
Sledge	Hell Rift
Torchlighter	Gardens of Hope
Clear	Location
Hell Rift	?
Cursed Event	Location
The Cursed Chapel	The Silver Spire
The Cursed Dais	Gardens of Hope

Act V

Kill	Location
Adria	The Great Hall, Ruins of Corvus
Baethus	Battlefields of Eternity
Bloone	Realm of the Banished, Battlefields of Eternity
Burrask the Tunneler	Battlefields of Eternity
Lograth	?
Lu'ca	Paths of the Drowned
Malthael	Heart of the Fortress, Pandemonium Fortress
Magrethar	?
Matanzas the Loathsome	Westmarch Commons
Micheboar	Westmarch Heights
Obsidious	?
Purah	?
Sartor	Battlefields of Eternity
Slarth the Tunneler	?
Theodosia Buhre	Westmarch Heights
Urzael	Tower of Korelan, Westmarch Heights
Valtesk the Cruel	Pandemonium Fortress
Vec Marru	?
Vek Tabok	Path to the Corvus, Passage to Corvus
Vilepaw	Paths of the Drowned
Xaphne	Pandemonium Fortress
Event	Location
Altar of Sadness	Briarthorn Cemetery
The Burning Man	Paths of the Drowned
Cryptology	Briarthorn Cemetery
Firestorm	Westmarch Commons
Grave Situation	?
The Great Weapon	Battlefields of Eternity
Out of the Fire	?
Out of Time	Pandemonium Fortress
The Burning Man	Paths of the Drowned
The Last Stand	Westmarch Commons
The Lord of the Hill	Path of the Drowned]]
The Lost Legion	Battlefields of Eternity
The Rebellious Rabble	?
The True Son of the Wolf	?
Touch of Death	Westmarch Commons
The Great Weapon	?
Cursed Event	Location
The Cursed Bone Pit	Repository of Bones, Westmarch Heights
The Cursed City	Passage to Corvus, Paths of the Drowned

Gallery

Game Settings
Adventure mode Waypoint maps

SPOILER

Information below this point has been datamined from the Reaper of Souls PTR game files and as such should be considered a spoiler.

Datamining Bounties

In one of the panels of images datamined called 'WaypointMap' are icons now known to be bounty indicators. All the images on the panel are in pairs, one plain and one with a green tick over it, probably indicating completion.

It does not necessarily mean that all of the icons represent a type of Bounty. All the icons are below.

	Bounty with a random boss, and the completed icon.
	Bounty to complete an event, and the completed icon.
	Bounty to clear a dungeon, and the completed icon.
	Bounty with a quest or act boss.

	This could be something to do with the Devil's Hand as the icons are similar to the image panel labelled Devil's Hand in the data files
	This marks a completed bounty in a given act. When all five bounties are completed in a given act, a special random reward can be earned by visiting Tyrael in town.