Split piles are Kingdom card piles containing multiple differently named cards, in a particular order. Often, the cards in a split pile have some particular synergy with each other. Split piles were introduced in Empires and revisited in Allies. In Empires, the cards on top of the pile had to be gained or trashed before the cards on the bottom would be available; but Allies introduced the mechanism of rotating a split pile, allowing the top cards to be moved to the bottom of the pile to make the next cards accessible.
Dark Ages featured Knights and Ruins, a precursor to split piles; these supply piles contain multiple differently-named cards, but they are shuffled at the start of the game rather than appearing in a prescribed order.
The cards in a split pile usually have different costs and may belong to different card types. When an effect depends on the cost or types of a pile, rather than of an individual card, the information listed on a split pile's randomizer card determine what the cost and types of the pile as a whole are considered to be. For instance, the Gladiator/Fortune pile is labeled a Action pile, and therefore may be designated the Bane pile for Young Witch and have various Adventures tokens placed on it, even though Fortune is not an Action and costs more than ; and when this is the case, Fortune and Gladiator both receive the bonuses from the Adventures tokens and may be used as a Bane card.
 List of split pile cards
Piles are sorted by the cost of the top card (which is shown on the randomizer card for the pile).
 Official Rules
- Five Kingdom Card piles in Empires have two cards in them, with 5 copies of each - Catapult / Rocks, Encampment / Plunder, Gladiator / Fortune, Patrician / Emporium, and Settlers / Bustling Village.
- The Randomizers for those piles show both cards. During set-up, always put the cheaper card on top, e.g. Patrician (cost ) above Emporium (cost ).
- To mark the pile, turn the bottom half sideways. That way players remember that the other card is there. Turn it back when those cards are uncovered.
- Players may only Buy or Gain the top card of a pile; players have to work through the top 5 cards to get to the bottom 5.
- Players can read the covered card to remember what it does, but cannot buy it or gain it until it is uncovered.
- If the card is covered back up somehow - for example Encampment can return to its pile - then once again players cannot Buy or Gain the covered cards, until again uncovered.
- Returning cards to a pile, such as with Ambassador (from Dominion: Seaside), can also result in the pile being in an unusual order; an Ambassador could return a Plunder to the Encampment/Plunder pile on top of an Encampment.
- Some cards refer to the cost or types of a pile as if it is just one card. In these cases go with what is on the Randomizer card, which usually matches the top card.
- Some things refer to cards from a particular pile; these things work on both cards from a split pile.
- For example Training (from Dominion: Adventures) lets a player put a token on an Action pile, which causes them to get + when playing a card from that pile. The token can be put on the Catapult / Rocks pile, despite Rocks being a Treasure; and the token causes both Catapult and Rocks to produce an extra when played.
- Emptying the top half of a split pile does not count as emptying a pile, for the game end condition or cards that refer to empty piles. The entire pile needs to be gone for the pile to be empty.
- One Kingdom Card pile in Empires has 8 different cards - the Castles. They behave similarly to the other split piles; only the top card can be bought or gained, they go in order by cost with Humble Castle on top, and so on. This pile is treated as a Victory - Castle pile, as per the Randomizer, despite the top card being a Treasure - Victory - Castle. In 2-player games, use one of each Castle; with more players, use all 12 cards.
- Dominion: Allies has six split piles, that have four different cards in each of them.
- The cards start the game in order by cost. For example, the Augurs pile starts out with 4 Herb Gatherers on top, then 4 Acolytes, then 4 Sorceresses, then 4 Sibyls. This order may get messed up by cards like Swap; that's fine.
- As with the split piles in Dominion: Empires, only the top card of a split pile can be bought or gained.
- You can look through the cards in a split pile at any time, without changing the order.
- The top card of each split pile has an ability that can "rotate" the pile (or with Battle Plan, any pile). Rotating a pile means taking the top card, and all copies of it directly under it, and putting them on the bottom. For example, if three Herb Gatherers were at the top of the Augurs, followed by Acolytes, you would put those three Herb Gatherers on the bottom, and Acolyte would now be on top.
- Some cards refer to information about a pile as if it's just one card. In these cases, go with what's on the Randomizer card, which usually matches the top card.
- Some things refer to cards from a particular pile; these things work on all cards from a split pile. For example Training (from Dominion: Adventures) lets a player put a token on an Action pile, which causes them to get + when playing a card from that pile. The token can be put on the Odyssey pile, and then Sunken Treasure will also make + when played.
 Secret History (Empires)
 Secret History (Allies)
 Why are Empires split piles 10 cards?
 Split pile synergies
 Allies split pile complexity