diff --git a/cmd/viewcore/html.go b/cmd/viewcore/html.go
index 8756b8b..564a547 100644
--- a/cmd/viewcore/html.go
+++ b/cmd/viewcore/html.go
@@ -11,8 +11,8 @@
 	"net/http"
 	"strconv"
 
-	"golang.org/x/debug/core"
-	"golang.org/x/debug/gocore"
+	"golang.org/x/debug/internal/core"
+	"golang.org/x/debug/internal/gocore"
 )
 
 func serveHTML(c *gocore.Process) {
diff --git a/cmd/viewcore/main.go b/cmd/viewcore/main.go
index fab34c7..acd0b7e 100644
--- a/cmd/viewcore/main.go
+++ b/cmd/viewcore/main.go
@@ -16,8 +16,8 @@
 	"text/tabwriter"
 
 	"github.com/spf13/cobra"
-	"golang.org/x/debug/core"
-	"golang.org/x/debug/gocore"
+	"golang.org/x/debug/internal/core"
+	"golang.org/x/debug/internal/gocore"
 )
 
 var cmdRoot = &cobra.Command{
diff --git a/core/address.go b/internal/core/address.go
similarity index 100%
rename from core/address.go
rename to internal/core/address.go
diff --git a/core/core_test.go b/internal/core/core_test.go
similarity index 100%
rename from core/core_test.go
rename to internal/core/core_test.go
diff --git a/core/mapping.go b/internal/core/mapping.go
similarity index 100%
rename from core/mapping.go
rename to internal/core/mapping.go
diff --git a/core/process.go b/internal/core/process.go
similarity index 100%
rename from core/process.go
rename to internal/core/process.go
diff --git a/core/read.go b/internal/core/read.go
similarity index 100%
rename from core/read.go
rename to internal/core/read.go
diff --git a/core/testdata/README b/internal/core/testdata/README
similarity index 100%
rename from core/testdata/README
rename to internal/core/testdata/README
diff --git a/core/testdata/core b/internal/core/testdata/core
similarity index 100%
rename from core/testdata/core
rename to internal/core/testdata/core
Binary files differ
diff --git a/core/testdata/tmp/test b/internal/core/testdata/tmp/test
similarity index 100%
rename from core/testdata/tmp/test
rename to internal/core/testdata/tmp/test
Binary files differ
diff --git a/core/thread.go b/internal/core/thread.go
similarity index 100%
rename from core/thread.go
rename to internal/core/thread.go
diff --git a/gocore/dominator.go b/internal/gocore/dominator.go
similarity index 100%
rename from gocore/dominator.go
rename to internal/gocore/dominator.go
diff --git a/gocore/dominator_test.go b/internal/gocore/dominator_test.go
similarity index 100%
rename from gocore/dominator_test.go
rename to internal/gocore/dominator_test.go
diff --git a/gocore/dwarf.go b/internal/gocore/dwarf.go
similarity index 99%
rename from gocore/dwarf.go
rename to internal/gocore/dwarf.go
index fffe950..513a5f3 100644
--- a/gocore/dwarf.go
+++ b/internal/gocore/dwarf.go
@@ -11,7 +11,7 @@
 	"sort"
 	"strings"
 
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 // read DWARF types from core dump.
diff --git a/gocore/gocore_test.go b/internal/gocore/gocore_test.go
similarity index 98%
rename from gocore/gocore_test.go
rename to internal/gocore/gocore_test.go
index 8d4206d..05679a0 100644
--- a/gocore/gocore_test.go
+++ b/internal/gocore/gocore_test.go
@@ -9,7 +9,7 @@
 	"reflect"
 	"testing"
 
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 // loadTest loads a simple core file which resulted from running the
diff --git a/gocore/goroutine.go b/internal/gocore/goroutine.go
similarity index 98%
rename from gocore/goroutine.go
rename to internal/gocore/goroutine.go
index b4891eb..2c6dbdd 100644
--- a/gocore/goroutine.go
+++ b/internal/gocore/goroutine.go
@@ -5,7 +5,7 @@
 package gocore
 
 import (
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 type Goroutine struct {
diff --git a/gocore/module.go b/internal/gocore/module.go
similarity index 98%
rename from gocore/module.go
rename to internal/gocore/module.go
index 93b5451..fe86162 100644
--- a/gocore/module.go
+++ b/internal/gocore/module.go
@@ -8,7 +8,7 @@
 	"fmt"
 	"sort"
 
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 type module struct {
diff --git a/gocore/object.go b/internal/gocore/object.go
similarity index 99%
rename from gocore/object.go
rename to internal/gocore/object.go
index debf0ca..5765959 100644
--- a/gocore/object.go
+++ b/internal/gocore/object.go
@@ -8,7 +8,7 @@
 	"math/bits"
 	"strings"
 
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 // An Object represents a single reachable object in the Go heap.
diff --git a/gocore/process.go b/internal/gocore/process.go
similarity index 99%
rename from gocore/process.go
rename to internal/gocore/process.go
index 5a88ef6..d12feed 100644
--- a/gocore/process.go
+++ b/internal/gocore/process.go
@@ -9,7 +9,7 @@
 	"fmt"
 	"strings"
 
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 // A Process represents the state of a Go process that core dumped.
diff --git a/gocore/region.go b/internal/gocore/region.go
similarity index 98%
rename from gocore/region.go
rename to internal/gocore/region.go
index cc78518..a8145d4 100644
--- a/gocore/region.go
+++ b/internal/gocore/region.go
@@ -4,7 +4,7 @@
 
 package gocore
 
-import "golang.org/x/debug/core"
+import "golang.org/x/debug/internal/core"
 
 // A region is a piece of the virtual address space of the inferior.
 // It has an address and a type.
diff --git a/gocore/reverse.go b/internal/gocore/reverse.go
similarity index 98%
rename from gocore/reverse.go
rename to internal/gocore/reverse.go
index 350374d..21cea17 100644
--- a/gocore/reverse.go
+++ b/internal/gocore/reverse.go
@@ -7,7 +7,7 @@
 import (
 	"sort"
 
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 func (p *Process) reverseEdges() {
diff --git a/gocore/root.go b/internal/gocore/root.go
similarity index 94%
rename from gocore/root.go
rename to internal/gocore/root.go
index 89a1ce8..2c7aade 100644
--- a/gocore/root.go
+++ b/internal/gocore/root.go
@@ -5,7 +5,7 @@
 package gocore
 
 import (
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 // A Root is an area of memory that might have pointers into the Go heap.
diff --git a/gocore/testdata/README b/internal/gocore/testdata/README
similarity index 100%
rename from gocore/testdata/README
rename to internal/gocore/testdata/README
diff --git a/gocore/testdata/core b/internal/gocore/testdata/core
similarity index 100%
rename from gocore/testdata/core
rename to internal/gocore/testdata/core
Binary files differ
diff --git a/gocore/testdata/core1.10 b/internal/gocore/testdata/core1.10
similarity index 100%
rename from gocore/testdata/core1.10
rename to internal/gocore/testdata/core1.10
Binary files differ
diff --git a/gocore/testdata/tmp/test b/internal/gocore/testdata/tmp/test
similarity index 100%
rename from gocore/testdata/tmp/test
rename to internal/gocore/testdata/tmp/test
Binary files differ
diff --git a/gocore/testdata/tmp/test1.10 b/internal/gocore/testdata/tmp/test1.10
similarity index 100%
rename from gocore/testdata/tmp/test1.10
rename to internal/gocore/testdata/tmp/test1.10
Binary files differ
diff --git a/gocore/type.go b/internal/gocore/type.go
similarity index 99%
rename from gocore/type.go
rename to internal/gocore/type.go
index 49e6c64..05ba59b 100644
--- a/gocore/type.go
+++ b/internal/gocore/type.go
@@ -8,7 +8,7 @@
 	"fmt"
 	"strings"
 
-	"golang.org/x/debug/core"
+	"golang.org/x/debug/internal/core"
 )
 
 // A Type is the representation of the type of a Go object.