diff --git a/cartographer/mapping/internal/2d/pose_graph_2d.h b/cartographer/mapping/internal/2d/pose_graph_2d.h
index 3f34e17..ab2d561 100644
--- a/cartographer/mapping/internal/2d/pose_graph_2d.h
+++ b/cartographer/mapping/internal/2d/pose_graph_2d.h
@@ -35,9 +35,9 @@
 #include "cartographer/mapping/2d/submap_2d.h"
 #include "cartographer/mapping/internal/2d/pose_graph/constraint_builder_2d.h"
 #include "cartographer/mapping/internal/2d/pose_graph/optimization_problem_2d.h"
+#include "cartographer/mapping/internal/trajectory_connectivity_state.h"
 #include "cartographer/mapping/pose_graph.h"
 #include "cartographer/mapping/pose_graph_trimmer.h"
-#include "cartographer/mapping/trajectory_connectivity_state.h"
 #include "cartographer/sensor/fixed_frame_pose_data.h"
 #include "cartographer/sensor/landmark_data.h"
 #include "cartographer/sensor/odometry_data.h"
diff --git a/cartographer/mapping/internal/3d/pose_graph_3d.h b/cartographer/mapping/internal/3d/pose_graph_3d.h
index 4d5cde4..f4d1553 100644
--- a/cartographer/mapping/internal/3d/pose_graph_3d.h
+++ b/cartographer/mapping/internal/3d/pose_graph_3d.h
@@ -35,9 +35,9 @@
 #include "cartographer/mapping/3d/submap_3d.h"
 #include "cartographer/mapping/internal/3d/pose_graph/constraint_builder_3d.h"
 #include "cartographer/mapping/internal/3d/pose_graph/optimization_problem_3d.h"
+#include "cartographer/mapping/internal/trajectory_connectivity_state.h"
 #include "cartographer/mapping/pose_graph.h"
 #include "cartographer/mapping/pose_graph_trimmer.h"
-#include "cartographer/mapping/trajectory_connectivity_state.h"
 #include "cartographer/sensor/fixed_frame_pose_data.h"
 #include "cartographer/sensor/landmark_data.h"
 #include "cartographer/sensor/odometry_data.h"
diff --git a/cartographer/mapping/collated_trajectory_builder.cc b/cartographer/mapping/internal/collated_trajectory_builder.cc
similarity index 97%
rename from cartographer/mapping/collated_trajectory_builder.cc
rename to cartographer/mapping/internal/collated_trajectory_builder.cc
index 4245988..d4d2e1d 100644
--- a/cartographer/mapping/collated_trajectory_builder.cc
+++ b/cartographer/mapping/internal/collated_trajectory_builder.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/mapping/collated_trajectory_builder.h"
+#include "cartographer/mapping/internal/collated_trajectory_builder.h"
 
 #include "cartographer/common/time.h"
 #include "glog/logging.h"
diff --git a/cartographer/mapping/collated_trajectory_builder.h b/cartographer/mapping/internal/collated_trajectory_builder.h
similarity index 94%
rename from cartographer/mapping/collated_trajectory_builder.h
rename to cartographer/mapping/internal/collated_trajectory_builder.h
index 6d4ebf1..1612cec 100644
--- a/cartographer/mapping/collated_trajectory_builder.h
+++ b/cartographer/mapping/internal/collated_trajectory_builder.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_MAPPING_COLLATED_TRAJECTORY_BUILDER_H_
-#define CARTOGRAPHER_MAPPING_COLLATED_TRAJECTORY_BUILDER_H_
+#ifndef CARTOGRAPHER_MAPPING_INTERNAL_COLLATED_TRAJECTORY_BUILDER_H_
+#define CARTOGRAPHER_MAPPING_INTERNAL_COLLATED_TRAJECTORY_BUILDER_H_
 
 #include <chrono>
 #include <map>
@@ -100,4 +100,4 @@ class CollatedTrajectoryBuilder : public TrajectoryBuilderInterface {
 }  // namespace mapping
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_MAPPING_COLLATED_TRAJECTORY_BUILDER_H_
+#endif  // CARTOGRAPHER_MAPPING_INTERNAL_COLLATED_TRAJECTORY_BUILDER_H_
diff --git a/cartographer/mapping/connected_components.cc b/cartographer/mapping/internal/connected_components.cc
similarity index 98%
rename from cartographer/mapping/connected_components.cc
rename to cartographer/mapping/internal/connected_components.cc
index c9e8601..b3a4ecd 100644
--- a/cartographer/mapping/connected_components.cc
+++ b/cartographer/mapping/internal/connected_components.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/mapping/connected_components.h"
+#include "cartographer/mapping/internal/connected_components.h"
 
 #include <algorithm>
 #include <unordered_set>
diff --git a/cartographer/mapping/connected_components.h b/cartographer/mapping/internal/connected_components.h
similarity index 94%
rename from cartographer/mapping/connected_components.h
rename to cartographer/mapping/internal/connected_components.h
index 6899e80..44e7e64 100644
--- a/cartographer/mapping/connected_components.h
+++ b/cartographer/mapping/internal/connected_components.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_MAPPING_CONNECTED_COMPONENTS_H_
-#define CARTOGRAPHER_MAPPING_CONNECTED_COMPONENTS_H_
+#ifndef CARTOGRAPHER_MAPPING_INTERNAL_CONNECTED_COMPONENTS_H_
+#define CARTOGRAPHER_MAPPING_INTERNAL_CONNECTED_COMPONENTS_H_
 
 #include <map>
 #include <unordered_map>
@@ -87,4 +87,4 @@ proto::ConnectedComponents ToProto(
 }  // namespace mapping
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_MAPPING_CONNECTED_COMPONENTS_H_
+#endif  // CARTOGRAPHER_MAPPING_INTERNAL_CONNECTED_COMPONENTS_H_
diff --git a/cartographer/mapping/connected_components_test.cc b/cartographer/mapping/internal/connected_components_test.cc
similarity index 98%
rename from cartographer/mapping/connected_components_test.cc
rename to cartographer/mapping/internal/connected_components_test.cc
index 5bd9495..22feb8d 100644
--- a/cartographer/mapping/connected_components_test.cc
+++ b/cartographer/mapping/internal/connected_components_test.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/mapping/connected_components.h"
+#include "cartographer/mapping/internal/connected_components.h"
 
 #include <algorithm>
 #include <memory>
diff --git a/cartographer/mapping/trajectory_connectivity_state.cc b/cartographer/mapping/internal/trajectory_connectivity_state.cc
similarity index 97%
rename from cartographer/mapping/trajectory_connectivity_state.cc
rename to cartographer/mapping/internal/trajectory_connectivity_state.cc
index eb71610..2a9d57b 100644
--- a/cartographer/mapping/trajectory_connectivity_state.cc
+++ b/cartographer/mapping/internal/trajectory_connectivity_state.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/mapping/trajectory_connectivity_state.h"
+#include "cartographer/mapping/internal/trajectory_connectivity_state.h"
 
 namespace cartographer {
 namespace mapping {
diff --git a/cartographer/mapping/trajectory_connectivity_state.h b/cartographer/mapping/internal/trajectory_connectivity_state.h
similarity index 91%
rename from cartographer/mapping/trajectory_connectivity_state.h
rename to cartographer/mapping/internal/trajectory_connectivity_state.h
index 9b95bdb..1f7c386 100644
--- a/cartographer/mapping/trajectory_connectivity_state.h
+++ b/cartographer/mapping/internal/trajectory_connectivity_state.h
@@ -14,11 +14,11 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_MAPPING_TRAJECTORY_CONNECTIVITY_STATE_H_
-#define CARTOGRAPHER_MAPPING_TRAJECTORY_CONNECTIVITY_STATE_H_
+#ifndef CARTOGRAPHER_MAPPING_INTERNAL_TRAJECTORY_CONNECTIVITY_STATE_H_
+#define CARTOGRAPHER_MAPPING_INTERNAL_TRAJECTORY_CONNECTIVITY_STATE_H_
 
 #include "cartographer/common/time.h"
-#include "cartographer/mapping/connected_components.h"
+#include "cartographer/mapping/internal/connected_components.h"
 
 namespace cartographer {
 namespace mapping {
@@ -73,4 +73,4 @@ class TrajectoryConnectivityState {
 }  // namespace mapping
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_MAPPING_TRAJECTORY_CONNECTIVITY_STATE_H_
+#endif  // CARTOGRAPHER_MAPPING_INTERNAL_TRAJECTORY_CONNECTIVITY_STATE_H_
diff --git a/cartographer/mapping/trajectory_connectivity_state_test.cc b/cartographer/mapping/internal/trajectory_connectivity_state_test.cc
similarity index 97%
rename from cartographer/mapping/trajectory_connectivity_state_test.cc
rename to cartographer/mapping/internal/trajectory_connectivity_state_test.cc
index 68ed26c..f56e695 100644
--- a/cartographer/mapping/trajectory_connectivity_state_test.cc
+++ b/cartographer/mapping/internal/trajectory_connectivity_state_test.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/mapping/trajectory_connectivity_state.h"
+#include "cartographer/mapping/internal/trajectory_connectivity_state.h"
 
 #include "gtest/gtest.h"
 
diff --git a/cartographer/mapping/map_builder.cc b/cartographer/mapping/map_builder.cc
index 38fa47b..c6aac76 100644
--- a/cartographer/mapping/map_builder.cc
+++ b/cartographer/mapping/map_builder.cc
@@ -24,11 +24,11 @@
 
 #include "cartographer/common/make_unique.h"
 #include "cartographer/common/time.h"
-#include "cartographer/mapping/collated_trajectory_builder.h"
 #include "cartographer/mapping/internal/2d/local_trajectory_builder_2d.h"
 #include "cartographer/mapping/internal/2d/pose_graph_2d.h"
 #include "cartographer/mapping/internal/3d/local_trajectory_builder_3d.h"
 #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/sensor/collator.h"
 #include "cartographer/sensor/range_data.h"