> ## Documentation Index
> Fetch the complete documentation index at: https://hedera-0c6e0218-mintlify-4a9eb0b1.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# RealmID

> Hedera protobuf reference for the RealmID message, a unique realm identifier within a shard used to group accounts, files, and contracts on Hashgraph.

The ID for a realm. Within a given shard, every realm has a unique ID. Each account, file, and contract instance belongs to exactly one realm.

| Field      | Description                    |
| ---------- | ------------------------------ |
| `shardNum` | The shard number (nonnegative) |
| `realmNum` | The realm number (nonnegative) |