diff --git a/cmd/geth/config.go b/cmd/geth/config.go
index 3fe8bd7668..b450dd9c8b 100644
--- a/cmd/geth/config.go
+++ b/cmd/geth/config.go
@@ -150,6 +150,9 @@ func makeFullNode(ctx *cli.Context) *node.Node {
 	if ctx.GlobalIsSet(utils.OverrideIstanbulFlag.Name) {
 		cfg.Eth.OverrideIstanbul = new(big.Int).SetUint64(ctx.GlobalUint64(utils.OverrideIstanbulFlag.Name))
 	}
+	if ctx.GlobalIsSet(utils.OverrideMuirGlacierFlag.Name) {
+		cfg.Eth.OverrideMuirGlacier = new(big.Int).SetUint64(ctx.GlobalUint64(utils.OverrideMuirGlacierFlag.Name))
+	}
 	utils.RegisterEthService(stack, &cfg.Eth)
 
 	// Whisper must be explicitly enabled by specifying at least 1 whisper flag or in dev mode
diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index 7cfa3e8adf..80ab0a44d8 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -70,6 +70,7 @@ var (
 		utils.NoUSBFlag,
 		utils.SmartCardDaemonPathFlag,
 		utils.OverrideIstanbulFlag,
+		utils.OverrideMuirGlacierFlag,
 		utils.EthashCacheDirFlag,
 		utils.EthashCachesInMemoryFlag,
 		utils.EthashCachesOnDiskFlag,
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 4780a81373..238577ee6e 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -226,6 +226,10 @@ var (
 		Name:  "override.istanbul",
 		Usage: "Manually specify Istanbul fork-block, overriding the bundled setting",
 	}
+	OverrideMuirGlacierFlag = cli.Uint64Flag{
+		Name:  "override.muirglacier",
+		Usage: "Manually specify Muir Glacier fork-block, overriding the bundled setting",
+	}
 	// Light server and client settings
 	LightLegacyServFlag = cli.IntFlag{ // Deprecated in favor of light.serve, remove in 2021
 		Name:  "lightserv",
diff --git a/core/genesis.go b/core/genesis.go
index df0c967980..e15cffda6b 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -152,10 +152,10 @@ func (e *GenesisMismatchError) Error() string {
 //
 // The returned chain configuration is never nil.
 func SetupGenesisBlock(db ethdb.Database, genesis *Genesis) (*params.ChainConfig, common.Hash, error) {
-	return SetupGenesisBlockWithOverride(db, genesis, nil)
+	return SetupGenesisBlockWithOverride(db, genesis, nil, nil)
 }
 
-func SetupGenesisBlockWithOverride(db ethdb.Database, genesis *Genesis, overrideIstanbul *big.Int) (*params.ChainConfig, common.Hash, error) {
+func SetupGenesisBlockWithOverride(db ethdb.Database, genesis *Genesis, overrideIstanbul, overrideMuirGlacier *big.Int) (*params.ChainConfig, common.Hash, error) {
 	if genesis != nil && genesis.Config == nil {
 		return params.AllEthashProtocolChanges, common.Hash{}, errGenesisNoConfig
 	}
@@ -207,6 +207,9 @@ func SetupGenesisBlockWithOverride(db ethdb.Database, genesis *Genesis, override
 	if overrideIstanbul != nil {
 		newcfg.IstanbulBlock = overrideIstanbul
 	}
+	if overrideMuirGlacier != nil {
+		newcfg.MuirGlacierBlock = overrideMuirGlacier
+	}
 	if err := newcfg.CheckConfigForkOrder(); err != nil {
 		return newcfg, common.Hash{}, err
 	}
diff --git a/eth/backend.go b/eth/backend.go
index 83e05e96a8..adde609de0 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -135,7 +135,7 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 	if err != nil {
 		return nil, err
 	}
-	chainConfig, genesisHash, genesisErr := core.SetupGenesisBlockWithOverride(chainDb, config.Genesis, config.OverrideIstanbul)
+	chainConfig, genesisHash, genesisErr := core.SetupGenesisBlockWithOverride(chainDb, config.Genesis, config.OverrideIstanbul, config.OverrideMuirGlacier)
 	if _, ok := genesisErr.(*params.ConfigCompatError); genesisErr != nil && !ok {
 		return nil, genesisErr
 	}
diff --git a/eth/config.go b/eth/config.go
index 5094a533bf..8240391114 100644
--- a/eth/config.go
+++ b/eth/config.go
@@ -157,4 +157,7 @@ type Config struct {
 
 	// Istanbul block override (TODO: remove after the fork)
 	OverrideIstanbul *big.Int
+
+	// MuirGlacier block override (TODO: remove after the fork)
+	OverrideMuirGlacier *big.Int
 }
diff --git a/les/client.go b/les/client.go
index 1ad44e16d7..c460f4c09d 100644
--- a/les/client.go
+++ b/les/client.go
@@ -72,7 +72,8 @@ func New(ctx *node.ServiceContext, config *eth.Config) (*LightEthereum, error) {
 	if err != nil {
 		return nil, err
 	}
-	chainConfig, genesisHash, genesisErr := core.SetupGenesisBlockWithOverride(chainDb, config.Genesis, config.OverrideIstanbul)
+	chainConfig, genesisHash, genesisErr := core.SetupGenesisBlockWithOverride(chainDb, config.Genesis,
+		config.OverrideIstanbul, config.OverrideMuirGlacier)
 	if _, isCompat := genesisErr.(*params.ConfigCompatError); genesisErr != nil && !isCompat {
 		return nil, genesisErr
 	}