diff --git a/uniswap/constants.py b/uniswap/constants.py
index 436634b..f887601 100644
--- a/uniswap/constants.py
+++ b/uniswap/constants.py
@@ -6,11 +6,14 @@
     1: "mainnet",
     3: "ropsten",
     4: "rinkeby",
+    10: "optimism",
     42: "kovan",
     56: "binance",
     97: "binance_testnet",
     137: "polygon",
     100: "xdai",
+    42161: "arbitrum",
+    421611: "arbitrum_testnet",
 }
 
 _factory_contract_addresses_v1 = {