diff --git a/cartographer/cloud/internal/handlers/load_state_handler.cc b/cartographer/cloud/internal/handlers/load_state_handler.cc
index 3bb3330..9605ad9 100644
--- a/cartographer/cloud/internal/handlers/load_state_handler.cc
+++ b/cartographer/cloud/internal/handlers/load_state_handler.cc
@@ -20,7 +20,6 @@
 #include "cartographer/cloud/internal/map_builder_context_interface.h"
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
 #include "cartographer/common/make_unique.h"
-#include "cartographer/io/in_memory_proto_stream.h"
 #include "google/protobuf/empty.pb.h"
 
 namespace cartographer {
diff --git a/cartographer/cloud/internal/handlers/load_state_handler.h b/cartographer/cloud/internal/handlers/load_state_handler.h
index 9dae7c7..509e26b 100644
--- a/cartographer/cloud/internal/handlers/load_state_handler.h
+++ b/cartographer/cloud/internal/handlers/load_state_handler.h
@@ -19,7 +19,7 @@
 
 #include "cartographer/cloud/internal/framework/rpc_handler.h"
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
-#include "cartographer/io/in_memory_proto_stream.h"
+#include "cartographer/io/internal/in_memory_proto_stream.h"
 #include "google/protobuf/empty.pb.h"
 
 namespace cartographer {
diff --git a/cartographer/cloud/internal/handlers/write_state_handler.cc b/cartographer/cloud/internal/handlers/write_state_handler.cc
index 158d942..0f7cb1f 100644
--- a/cartographer/cloud/internal/handlers/write_state_handler.cc
+++ b/cartographer/cloud/internal/handlers/write_state_handler.cc
@@ -20,8 +20,7 @@
 #include "cartographer/cloud/internal/map_builder_context_interface.h"
 #include "cartographer/cloud/internal/map_builder_server.h"
 #include "cartographer/cloud/proto/map_builder_service.pb.h"
-#include "cartographer/common/make_unique.h"
-#include "cartographer/io/in_memory_proto_stream.h"
+#include "cartographer/io/internal/in_memory_proto_stream.h"
 
 namespace cartographer {
 namespace cloud {
diff --git a/cartographer/io/in_memory_proto_stream.cc b/cartographer/io/internal/in_memory_proto_stream.cc
similarity index 94%
rename from cartographer/io/in_memory_proto_stream.cc
rename to cartographer/io/internal/in_memory_proto_stream.cc
index 1be991e..4512b9b 100644
--- a/cartographer/io/in_memory_proto_stream.cc
+++ b/cartographer/io/internal/in_memory_proto_stream.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/io/in_memory_proto_stream.h"
+#include "cartographer/io/internal/in_memory_proto_stream.h"
 
 #include "glog/logging.h"
 
diff --git a/cartographer/io/in_memory_proto_stream.h b/cartographer/io/internal/in_memory_proto_stream.h
similarity index 93%
rename from cartographer/io/in_memory_proto_stream.h
rename to cartographer/io/internal/in_memory_proto_stream.h
index 47e9ea2..1ddb49d 100644
--- a/cartographer/io/in_memory_proto_stream.h
+++ b/cartographer/io/internal/in_memory_proto_stream.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_IO_IN_MEMORY_PROTO_STREAM_H_
-#define CARTOGRAPHER_IO_IN_MEMORY_PROTO_STREAM_H_
+#ifndef CARTOGRAPHER_IO_INTERNAL_IN_MEMORY_PROTO_STREAM_H_
+#define CARTOGRAPHER_IO_INTERNAL_IN_MEMORY_PROTO_STREAM_H_
 
 #include <queue>
 
@@ -75,4 +75,4 @@ class InMemoryProtoStreamReader
 }  // namespace io
 }  // namespace cartographer
 
-#endif  // CARTOGRAPHER_IO_IN_MEMORY_PROTO_STREAM_H_
+#endif  // CARTOGRAPHER_IO_INTERNAL_IN_MEMORY_PROTO_STREAM_H_
diff --git a/cartographer/io/in_memory_proto_stream_test.cc b/cartographer/io/internal/in_memory_proto_stream_test.cc
similarity index 97%
rename from cartographer/io/in_memory_proto_stream_test.cc
rename to cartographer/io/internal/in_memory_proto_stream_test.cc
index f2ef8dc..b033385 100644
--- a/cartographer/io/in_memory_proto_stream_test.cc
+++ b/cartographer/io/internal/in_memory_proto_stream_test.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer/io/in_memory_proto_stream.h"
+#include "cartographer/io/internal/in_memory_proto_stream.h"
 #include "cartographer/mapping/proto/pose_graph.pb.h"
 #include "cartographer/mapping/proto/serialization.pb.h"
 
diff --git a/cartographer/mapping/map_builder_interface.h b/cartographer/mapping/map_builder_interface.h
index ab9946b..5b0cbe3 100644
--- a/cartographer/mapping/map_builder_interface.h
+++ b/cartographer/mapping/map_builder_interface.h
@@ -24,7 +24,7 @@
 #include "Eigen/Geometry"
 #include "cartographer/common/lua_parameter_dictionary.h"
 #include "cartographer/common/port.h"
-#include "cartographer/io/proto_stream.h"
+#include "cartographer/io/proto_stream_interface.h"
 #include "cartographer/mapping/id.h"
 #include "cartographer/mapping/pose_graph_interface.h"
 #include "cartographer/mapping/proto/submap_visualization.pb.h"