Maps in Path of Exile are special items, which open portals to - much more challenging and rewarding - map areas, so they are an important part of the endgame. Maps come in different rarities just like other items, and their modifiers can be changed with different currency, or orbs.

Our first maps usually drop from Act 8 in the campaign, with an increasing, almost guaranteed chance until we reach the Epilogue. Maps come in different tiers - higher tier meaning they open higher level zones - and our first maps usually drop as Tier 1, and an area level of 68. The highest map tier is 17, containing monsters between 78 and 84.

There is a special world object called Map Device where we are using our maps and map fragments, and they open six Portals, each disappearing after we enter - so we only have a limited number of chances to leave and rejoin maps. After we complete our first Map, Officer Kirac will show us the Atlas of Worlds, where our completed maps will be revealed, so we can check our progression. Only maps that were already completed, or those that "connect" to these on the Atlas, can drop in a map area. We can also socket special Voidstones into the Atlas to raise the existing tier of Maps, and in this way we have chances of obtaining Tier 17 maps. Sextants can be used on Voidstones to add or reroll their modifiers.

Three maps of the same tier can be sold to a vendor to get a map one tier higher. Several currency items can be used on maps too, just like on armour or weapons - for example an Orb of Alchemy, or an Orb of Alteration - giving monsters or items spawned in the map different modifiers. Using a Vaal Orb on a map makes the last boss of the map Corrupted too, giving a chance to drop Vaal Fragments or Vaal Skill Gems. You can also use maps without identifying them, getting a bonus to the quantity of items dropped on the map. Running on unidentified rare or corrupted maps can be sometimes challenging because the modifiers are unknown, so you will need a strong character to complete them. Corrupted maps can only be modified with Tainted currencies which drop from Beyond demons.

Map fragments are special map items which can be used as a full set in certain order, to open portals to different high level areas. Using a Sacrifice Set - Sacrifice at Dusk, Dawn, Noon and Midnight - opens portals to the Apex of Sacrifice so we can challenge Queen Atziri. Or using a Mortal Set - Mortal Grief, Ignorance, Hope or Rage - opens portals to the Alluring Abyss where an even stronger version of Queen Atziri will be encountered. There are many other of these fragment sets in Path of Exile, granting entry to the Elder Guardians, the Shaper, or Sirus. These endgame encounters are usually very challenging and need a strong character to complete - but the possible rewards worth the risk. They can drop items which can only be acquired from these areas.

After unlocking the Atlas of Worlds, we also get access to the Atlas Passive Skill Tree. This looks a bit overwhelming at first, but it works similarly to our Passive Skill Tree, except its for Maps. It also has small passives, as well as Notable and Keystone passives, just like our regular Passive Skill Tree. We get Atlas Passive Skill Points by completing maps for the first time, killing Pinnacle Bosses, and completing Maven's Invitations. We can refund already spent Atlas Passives with an Orb of Unmaking, which works the same way as an Orb of Regret. We can also unlock two additional of these atlas trees, by progressing in the Atlas of Worlds and reaching certain milestones.

Maps can also drop as an influenced base, getting one from the three type of influences: Shaper, Elder and Conqueror. These maps contain monster packs that can drop influenced items. Influenced items can have special powerful stats that only exists on these items, and they can only drop from influenced monsters or bosses. Influenced maps may contain bosses which drop map fragments - which in turn open a way to their respective Pinnacle Boss. 

Blighted maps can drop from Blight encounters in any map, which gives us a much more challenging Blight encounter with better loot.

Understanding the deep Map system of Path of Exile is a crucial part to face and beat the most difficult challenges of the end game, and compete for the best loot drops available.