diff --git a/src/UglyToad.PdfPig/Geometry/GeometryExtensions.cs b/src/UglyToad.PdfPig/Geometry/GeometryExtensions.cs
index d4cfc4dd..d5d374e0 100644
--- a/src/UglyToad.PdfPig/Geometry/GeometryExtensions.cs
+++ b/src/UglyToad.PdfPig/Geometry/GeometryExtensions.cs
@@ -167,7 +167,7 @@
         /// </summary>
         /// <param name="points">The points.</param>
         /// <returns></returns>
-        public static PdfRectangle OrientedBoundingBox(IReadOnlyList<PdfPoint> points)
+        internal static PdfRectangle OrientedBoundingBox(IReadOnlyList<PdfPoint> points)
         {
             if (points == null || points.Count < 2)
             {