Orphan Blocks

What Is an Orphan Block?
  • In blockchain terms, orphan blocks are blocks mined at the same time as another block but not accepted by the blockchain.
    • Most of the time, this is because there are not enough blocks generated from that block for the network to recognize it as the longest fork.
    • The Bitcoin blockchain discards orphan blocks; however, other blockchains may use them for different purposes.
  • Technically, orphan blocks are called stale blocks, but because most people refer to them as orphaned, the name orphan block has stuck.


  • An orphan block is a block that has been solved within the blockchain network but was not accepted by the network.
  • There can be two miners who solve valid blocks simultaneously. The network uses both blocks until one chain has more verified blocks than the other. Then, the blocks in the shorter chain are orphaned.
  • Orphan blocks are a regular occurrence in a distributed blockchain such as Bitcoin and Ethereum.