diff --git a/cmd/gouroboros/query.go b/cmd/gouroboros/query.go
index 71542cdd..f86935ea 100644
--- a/cmd/gouroboros/query.go
+++ b/cmd/gouroboros/query.go
@@ -305,6 +305,13 @@ func testQuery(f *globalFlags) {
 				}
 			}
 		}
+	case "proposed-protocol-params-updates":
+		proposedUpdates, err := o.LocalStateQuery().Client.GetProposedProtocolParamsUpdates()
+		if err != nil {
+			fmt.Printf("ERROR: failure querying proposed protocol params updates: %s\n", err)
+			os.Exit(1)
+		}
+		fmt.Printf("proposed-protocol-params-updates: %v\n", *proposedUpdates)
 	default:
 		fmt.Printf("ERROR: unknown query: %s\n", queryFlags.flagset.Args()[0])
 		os.Exit(1)
diff --git a/ledger/common/common.go b/ledger/common/common.go
index 15a9a9b8..4975c4d6 100644
--- a/ledger/common/common.go
+++ b/ledger/common/common.go
@@ -110,6 +110,9 @@ func Blake2b224Hash(data []byte) Blake2b224 {
 	return Blake2b224(tmpHash.Sum(nil))
 }
 
+// GenesisHash is a type alias for the Blake2b-224 hash used for genesis keys
+type GenesisHash = Blake2b224
+
 type Blake2b160 [Blake2b160Size]byte
 
 func NewBlake2b160(data []byte) Blake2b160 {
diff --git a/protocol/localstatequery/queries.go b/protocol/localstatequery/queries.go
index cf2fb093..a81b2526 100644
--- a/protocol/localstatequery/queries.go
+++ b/protocol/localstatequery/queries.go
@@ -21,6 +21,7 @@ import (
 
 	"github.com/blinklabs-io/gouroboros/cbor"
 	"github.com/blinklabs-io/gouroboros/ledger"
+	"github.com/blinklabs-io/gouroboros/ledger/common"
 )
 
 // Query types
@@ -521,8 +522,7 @@ type CurrentProtocolParamsResult interface {
 		any
 }
 
-// TODO (#861)
-type ProposedProtocolParamsUpdatesResult any
+type ProposedProtocolParamsUpdatesResult map[common.GenesisHash]common.ProtocolParameterUpdate
 
 type StakeDistributionResult struct {
 	cbor.StructAsArray