Chains 
The viem/chains entrypoint proxies the @wagmi/chains NPM package, an official wagmi package which contains references to popular EVM-compatible chains such as: Polygon, Optimism, Avalanche, and more.
Usage 
Import your chain from the entrypoint and use them in the consuming viem code:
tsx
import { createPublicClient, http } from 'viem'
import { avalanche } from 'viem/chains'
const client = createPublicClient({
  chain: avalanche,
  transport: http()
})Supported chains 
- mainnet
- goerli
- arbitrum
- arbitrumGoerli
- aurora
- auroraTestnet
- avalanche
- avalancheFuji
- baseGoerli
- boba
- bronos
- bronosTestnet
- bsc
- bscTestnet
- canto
- celo
- celoAlfajores
- crossbell
- evmos
- evmosTestnet
- fantom
- fantomTestnet
- filecoin
- filecoinCalibration
- filecoinHyperspace
- flare
- flareTestnet
- gnosis
- gnosisChiado
- harmonyOne
- iotex
- iotexTestnet
- metis
- metisGoerli
- moonbaseAlpha
- moonbeam
- moonriver
- okc
- optimism
- optimismGoerli
- polygon
- polygonMumbai
- polygonZkEvmTestnet
- sepolia
- shardeumSphinx
- songbird
- songbirdTestnet
- taraxa
- taraxaTestnet
- telos
- telosTestnet
- zhejiang
- zora
- zoraTestnet
- zkSync
- zkSyncTestnet
- foundry
- hardhat
- localhost
Want to add a chain that's not listed here? Head to the wagmi References monorepo and read the Contributing Guide before opening a pull request.
Build your own 
You can also extend wagmi to support other EVM-compatible chains by building your own chain object that inherits the Chain type.
ts
import { Chain } from 'viem'
export const avalanche = {
  id: 43_114,
  name: 'Avalanche',
  network: 'avalanche',
  nativeCurrency: {
    decimals: 18,
    name: 'Avalanche',
    symbol: 'AVAX',
  },
  rpcUrls: {
    public: { http: ['https://api.avax.network/ext/bc/C/rpc'] },
    default: { http: ['https://api.avax.network/ext/bc/C/rpc'] },
  },
  blockExplorers: {
    etherscan: { name: 'SnowTrace', url: 'https://snowtrace.io' },
    default: { name: 'SnowTrace', url: 'https://snowtrace.io' },
  },
  contracts: {
    multicall3: {
      address: '0xca11bde05977b3631167028862be2a173976ca11',
      blockCreated: 11_907_934,
    },
  },
} as const satisfies Chain
