diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeBase.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeBase.cs
index f9ab78d..5b215d7 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeBase.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/Ranges/XLRangeBase.cs
@@ -480,7 +480,7 @@
 
         public Boolean IsMerged()
         {
-            return CellsUsed().Any(c => c.IsMerged());
+            return Cells().Any(c => c.IsMerged());
         }
 
         public Boolean IsEmpty()
diff --git a/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs b/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
index 2b43d98..72feca3 100644
--- a/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
+++ b/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
@@ -15,6 +15,11 @@
             var wb = new XLWorkbook();
             var ws = wb.AddWorksheet("Sheet1");
 
+            ws.Range("A2:A3").Merge();
+            Console.WriteLine(ws.Range("A1:A2").IsMerged());
+            Console.WriteLine(ws.Range("A2:A3").IsMerged());
+            Console.WriteLine(ws.Range("A1:A4").IsMerged());
+            Console.WriteLine(ws.Range("A4:A5").IsMerged());
 
             Console.WriteLine("Done");
             Console.ReadKey();