diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessDebugger.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessDebugger.cpp
--- a/lldb/source/Plugins/Process/Windows/Common/ProcessDebugger.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/ProcessDebugger.cpp
@@ -441,7 +441,7 @@
   // AllocationBase is defined for MEM_COMMIT and MEM_RESERVE but not MEM_FREE.
   if (mem_info.State != MEM_FREE) {
     info.GetRange().SetRangeBase(
-        reinterpret_cast<addr_t>(mem_info.AllocationBase));
+        reinterpret_cast<addr_t>(mem_info.BaseAddress));
     info.GetRange().SetRangeEnd(reinterpret_cast<addr_t>(mem_info.BaseAddress) +
                                 mem_info.RegionSize);
     info.SetMapped(MemoryRegionInfo::eYes);
diff --git a/lldb/test/API/functionalities/memory-region/TestMemoryRegion.py b/lldb/test/API/functionalities/memory-region/TestMemoryRegion.py
--- a/lldb/test/API/functionalities/memory-region/TestMemoryRegion.py
+++ b/lldb/test/API/functionalities/memory-region/TestMemoryRegion.py
@@ -27,7 +27,7 @@
             substrs=["memory region <address-expression>",
                      "memory region -a"])
 
-    def test(self):
+    def setup_program(self):
         self.build()
 
         # Set breakpoint in main and run
@@ -37,6 +37,9 @@
 
         self.runCmd("run", RUN_SUCCEEDED)
 
+    def test_command(self):
+        self.setup_program()
+
         interp = self.dbg.GetCommandInterpreter()
         result = lldb.SBCommandReturnObject()
 
@@ -84,3 +87,23 @@
         interp.HandleCommand("memory region --all", result)
         self.assertTrue(result.Succeeded())
         self.assertEqual(result.GetOutput(), all_regions)
+
+    def test_unique_base_addresses(self):
+        # In the past on Windows we were recording AllocationBase as the base address
+        # of the current region, not BaseAddress. So if a range of pages was split
+        # into regions you would see several regions with the same base address.
+        # This checks that this no longer happens (and it shouldn't happen on any
+        # other OS either).
+        self.setup_program()
+
+        process = self.dbg.GetTargetAtIndex(0).GetProcess()
+        regions = process.GetMemoryRegions()
+        base_addresses = set()
+
+        for idx in range(regions.GetSize()):
+            region = lldb.SBMemoryRegionInfo()
+            regions.GetMemoryRegionAtIndex(idx, region)
+            base_address = region.GetRegionBase()
+            self.assertFalse(base_address in base_addresses,
+                "Did not expect to see a repeated base region address.")
+            base_addresses.add(base_address)
\ No newline at end of file