diff --git a/cartographer/mapping/map_builder.cc b/cartographer/mapping/map_builder.cc
index c93cd12..7809e6f 100644
--- a/cartographer/mapping/map_builder.cc
+++ b/cartographer/mapping/map_builder.cc
@@ -28,7 +28,6 @@
 #include "cartographer/mapping/internal/3d/pose_graph_3d.h"
 #include "cartographer/mapping/internal/collated_trajectory_builder.h"
 #include "cartographer/mapping/internal/global_trajectory_builder.h"
-#include "cartographer/mapping/proto/internal/legacy_serialized_data.pb.h"
 #include "cartographer/sensor/internal/collator.h"
 #include "cartographer/sensor/internal/trajectory_collator.h"
 #include "cartographer/sensor/internal/voxel_filter.h"
diff --git a/cartographer/mapping/proto/internal/legacy_probability_grid.proto b/cartographer/mapping/proto/internal/legacy_probability_grid.proto
deleted file mode 100644
index 58d9d68..0000000
--- a/cartographer/mapping/proto/internal/legacy_probability_grid.proto
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright 2016 The Cartographer Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-syntax = "proto3";
-
-package cartographer.mapping.proto;
-
-import "cartographer/mapping/proto/2d/map_limits.proto";
-
-// The legacy probability grid that was used before the generalized
-// grid structure was introduced.
-
-message LegacyProbabilityGrid {
-  message CellBox {
-    int32 max_x = 1;
-    int32 max_y = 2;
-    int32 min_x = 3;
-    int32 min_y = 4;
-  }
-
-  MapLimits limits = 1;
-  // These values are actually int16s, but protos don't have a native int16
-  // type.
-  repeated int32 cells = 2;
-  CellBox known_cells_box = 8;
-}
diff --git a/cartographer/mapping/proto/internal/legacy_serialized_data.proto b/cartographer/mapping/proto/internal/legacy_serialized_data.proto
deleted file mode 100644
index 56f9c6a..0000000
--- a/cartographer/mapping/proto/internal/legacy_serialized_data.proto
+++ /dev/null
@@ -1,42 +0,0 @@
-// Copyright 2018 The Cartographer Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-syntax = "proto3";
-
-package cartographer.mapping.proto;
-
-import "cartographer/mapping/proto/serialization.proto";
-import "cartographer/mapping/proto/internal/legacy_submap.proto";
-
-message LegacySerializedData {
-  Submap submap = 1;
-  Node node = 2;
-  ImuData imu_data = 3;
-  OdometryData odometry_data = 4;
-  FixedFramePoseData fixed_frame_pose_data = 5;
-  TrajectoryData trajectory_data = 6;
-  LandmarkData landmark_data = 7;
-}
-
-// For backwards compatibility with serialized data containing the legacy 
-// submap format that did not yet use the generalized 2D grid format.
-message LegacySerializedDataLegacySubmap {
-  LegacySubmap submap = 1;
-  Node node = 2;
-  ImuData imu_data = 3;
-  OdometryData odometry_data = 4;
-  FixedFramePoseData fixed_frame_pose_data = 5;
-  TrajectoryData trajectory_data = 6;
-  LandmarkData landmark_data = 7;
-}
diff --git a/cartographer/mapping/proto/internal/legacy_submap.proto b/cartographer/mapping/proto/internal/legacy_submap.proto
deleted file mode 100644
index 31ed41f..0000000
--- a/cartographer/mapping/proto/internal/legacy_submap.proto
+++ /dev/null
@@ -1,46 +0,0 @@
-// Copyright 2016 The Cartographer Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-syntax = "proto3";
-
-package cartographer.mapping.proto;
-
-import "cartographer/mapping/proto/pose_graph.proto";
-import "cartographer/mapping/proto/internal/legacy_probability_grid.proto";
-import "cartographer/mapping/proto/3d/hybrid_grid.proto";
-import "cartographer/transform/proto/transform.proto";
-
-// Serialized state of a Submap2D.
-// Uses the legacy, non-generalized probability grid format.
-message LegacySubmap2D {
-  transform.proto.Rigid3d local_pose = 1;
-  int32 num_range_data = 2;
-  bool finished = 3;
-  LegacyProbabilityGrid probability_grid = 4;
-}
-
-// Serialized state of a Submap3D.
-message LegacySubmap3D {
-  transform.proto.Rigid3d local_pose = 1;
-  int32 num_range_data = 2;
-  bool finished = 3;
-  HybridGrid high_resolution_hybrid_grid = 4;
-  HybridGrid low_resolution_hybrid_grid = 5;
-}
-
-message LegacySubmap {
-  SubmapId submap_id = 1;
-  LegacySubmap2D submap_2d = 2;
-  LegacySubmap3D submap_3d = 3;
-}