diff --git a/src/types/UiaTextRangeBase.cpp b/src/types/UiaTextRangeBase.cpp
index 804d4758540..9326809b8fc 100644
--- a/src/types/UiaTextRangeBase.cpp
+++ b/src/types/UiaTextRangeBase.cpp
@@ -181,9 +181,9 @@ const COORD UiaTextRangeBase::GetEndpoint(TextPatternRangeEndpoint endpoint) con
 // - val - the value that it will be set to
 // Return Value:
 // - true if range is degenerate, false otherwise.
-bool UiaTextRangeBase::SetEndpoint(TextPatternRangeEndpoint endpoint, const COORD val)
+bool UiaTextRangeBase::SetEndpoint(TextPatternRangeEndpoint endpoint, const COORD val) noexcept
 {
-    const auto bufferSize = _pData->GetTextBuffer().GetSize();
+    const auto bufferSize = _getBufferSize();
     switch (endpoint)
     {
     case TextPatternRangeEndpoint::TextPatternRangeEndpoint_End:
@@ -301,7 +301,7 @@ IFACEMETHODIMP UiaTextRangeBase::ExpandToEnclosingUnit(_In_ TextUnit unit) noexc
     try
     {
         const auto& buffer = _pData->GetTextBuffer();
-        const auto bufferSize = buffer.GetSize();
+        const auto bufferSize = _getBufferSize();
         const auto bufferEnd = bufferSize.EndExclusive();
 
         if (unit == TextUnit::TextUnit_Character)
@@ -314,6 +314,13 @@ IFACEMETHODIMP UiaTextRangeBase::ExpandToEnclosingUnit(_In_ TextUnit unit) noexc
             // expand to word
             _start = buffer.GetWordStart(_start, _wordDelimiters, true);
             _end = buffer.GetWordEnd(_start, _wordDelimiters, true);
+
+            // GetWordEnd may return the actual end of the TextBuffer.
+            // If so, just set it to this value of bufferEnd
+            if (!bufferSize.IsInBounds(_end))
+            {
+                _end = bufferEnd;
+            }
         }
         else if (unit <= TextUnit::TextUnit_Line)
         {
@@ -359,7 +366,7 @@ try
     *ppRetVal = nullptr;
 
     const std::wstring queryText{ text, SysStringLen(text) };
-    const auto bufferSize = _pData->GetTextBuffer().GetSize();
+    const auto bufferSize = _getBufferSize();
     const auto sensitivity = ignoreCase ? Search::Sensitivity::CaseInsensitive : Search::Sensitivity::CaseSensitive;
 
     auto searchDirection = Search::Direction::Forward;
@@ -436,7 +443,7 @@ IFACEMETHODIMP UiaTextRangeBase::GetBoundingRectangles(_Outptr_result_maybenull_
         // set of coords.
         std::vector<double> coords;
 
-        const auto bufferSize = _pData->GetTextBuffer().GetSize();
+        const auto bufferSize = _getBufferSize();
 
         // these viewport vars are converted to the buffer coordinate space
         const auto viewport = bufferSize.ConvertToOrigin(_pData->GetViewport());
@@ -970,6 +977,25 @@ const unsigned int UiaTextRangeBase::_getViewportHeight(const SMALL_RECT viewpor
     return viewport.Bottom - viewport.Top + 1;
 }
 
+// Routine Description:
+// - Gets a viewport representing where valid text may be in the TextBuffer
+// - Use this instead of `textBuffer.GetSize()`. This improves performance
+//    because it's a smaller space to have to search through
+// Arguments:
+// - <none>
+// Return Value:
+// - A viewport representing the portion of the TextBuffer that has valid text
+const Viewport UiaTextRangeBase::_getBufferSize() const noexcept
+{
+    // we need to add 1 to the X/Y of textBufferEnd
+    // because we want the returned viewport to include this COORD
+    const auto textBufferEnd = _pData->GetTextBufferEndPosition();
+    const auto width = base::ClampAdd<short>(1, textBufferEnd.X);
+    const auto height = base::ClampAdd<short>(1, textBufferEnd.Y);
+
+    return Viewport::FromDimensions({ 0, 0 }, width, height);
+}
+
 // Routine Description:
 // - adds the relevant coordinate points from the row to coords.
 // - it is assumed that startAnchor and endAnchor are within the same row
@@ -1038,7 +1064,7 @@ void UiaTextRangeBase::_getBoundingRect(_In_ const COORD startAnchor, _In_ const
 void UiaTextRangeBase::_moveEndpointByUnitCharacter(_In_ const int moveCount,
                                                     _In_ const TextPatternRangeEndpoint endpoint,
                                                     _Out_ gsl::not_null<int*> const pAmountMoved,
-                                                    _In_ const bool preventBufferEnd)
+                                                    _In_ const bool preventBufferEnd) noexcept
 {
     *pAmountMoved = 0;
 
@@ -1049,7 +1075,7 @@ void UiaTextRangeBase::_moveEndpointByUnitCharacter(_In_ const int moveCount,
 
     const bool allowBottomExclusive = !preventBufferEnd;
     const MovementDirection moveDirection = (moveCount > 0) ? MovementDirection::Forward : MovementDirection::Backward;
-    const auto bufferSize = _pData->GetTextBuffer().GetSize();
+    const auto bufferSize = _getBufferSize();
 
     bool success = true;
     auto target = GetEndpoint(endpoint);
@@ -1106,10 +1132,10 @@ void UiaTextRangeBase::_moveEndpointByUnitWord(_In_ const int moveCount,
     const bool allowBottomExclusive = !preventBufferEnd;
     const MovementDirection moveDirection = (moveCount > 0) ? MovementDirection::Forward : MovementDirection::Backward;
     const auto& buffer = _pData->GetTextBuffer();
-    const auto bufferSize = buffer.GetSize();
+    const auto bufferSize = _getBufferSize();
     const auto bufferOrigin = bufferSize.Origin();
     const auto bufferEnd = bufferSize.EndExclusive();
-    const auto lastCharPos = buffer.GetLastNonSpaceCharacter();
+    const auto lastCharPos = buffer.GetLastNonSpaceCharacter(bufferSize);
 
     auto resultPos = GetEndpoint(endpoint);
     auto nextPos = resultPos;
@@ -1180,7 +1206,7 @@ void UiaTextRangeBase::_moveEndpointByUnitWord(_In_ const int moveCount,
 void UiaTextRangeBase::_moveEndpointByUnitLine(_In_ const int moveCount,
                                                _In_ const TextPatternRangeEndpoint endpoint,
                                                _Out_ gsl::not_null<int*> const pAmountMoved,
-                                               _In_ const bool preventBufferEnd)
+                                               _In_ const bool preventBufferEnd) noexcept
 {
     *pAmountMoved = 0;
 
@@ -1191,7 +1217,7 @@ void UiaTextRangeBase::_moveEndpointByUnitLine(_In_ const int moveCount,
 
     const bool allowBottomExclusive = !preventBufferEnd;
     const MovementDirection moveDirection = (moveCount > 0) ? MovementDirection::Forward : MovementDirection::Backward;
-    const auto bufferSize = _pData->GetTextBuffer().GetSize();
+    const auto bufferSize = _getBufferSize();
 
     bool success = true;
     auto resultPos = GetEndpoint(endpoint);
@@ -1264,7 +1290,7 @@ void UiaTextRangeBase::_moveEndpointByUnitLine(_In_ const int moveCount,
 void UiaTextRangeBase::_moveEndpointByUnitDocument(_In_ const int moveCount,
                                                    _In_ const TextPatternRangeEndpoint endpoint,
                                                    _Out_ gsl::not_null<int*> const pAmountMoved,
-                                                   _In_ const bool preventBufferEnd)
+                                                   _In_ const bool preventBufferEnd) noexcept
 {
     *pAmountMoved = 0;
 
@@ -1274,7 +1300,7 @@ void UiaTextRangeBase::_moveEndpointByUnitDocument(_In_ const int moveCount,
     }
 
     const MovementDirection moveDirection = (moveCount > 0) ? MovementDirection::Forward : MovementDirection::Backward;
-    const auto bufferSize = _pData->GetTextBuffer().GetSize();
+    const auto bufferSize = _getBufferSize();
 
     const auto target = GetEndpoint(endpoint);
     switch (moveDirection)
diff --git a/src/types/UiaTextRangeBase.hpp b/src/types/UiaTextRangeBase.hpp
index 389807b0d31..aa56a3c4261 100644
--- a/src/types/UiaTextRangeBase.hpp
+++ b/src/types/UiaTextRangeBase.hpp
@@ -87,7 +87,7 @@ namespace Microsoft::Console::Types
 
         const IdType GetId() const noexcept;
         const COORD GetEndpoint(TextPatternRangeEndpoint endpoint) const noexcept;
-        bool SetEndpoint(TextPatternRangeEndpoint endpoint, const COORD val);
+        bool SetEndpoint(TextPatternRangeEndpoint endpoint, const COORD val) noexcept;
         const bool IsDegenerate() const noexcept;
 
         // ITextRangeProvider methods
@@ -159,6 +159,7 @@ namespace Microsoft::Console::Types
 
         virtual const COORD _getScreenFontSize() const;
         const unsigned int _getViewportHeight(const SMALL_RECT viewport) const noexcept;
+        const Viewport _getBufferSize() const noexcept;
 
         void _getBoundingRect(_In_ const COORD startAnchor, _In_ const COORD endAnchor, _Inout_ std::vector<double>& coords) const;
 
@@ -166,7 +167,7 @@ namespace Microsoft::Console::Types
         _moveEndpointByUnitCharacter(_In_ const int moveCount,
                                      _In_ const TextPatternRangeEndpoint endpoint,
                                      _Out_ gsl::not_null<int*> const pAmountMoved,
-                                     _In_ const bool preventBufferEnd = false);
+                                     _In_ const bool preventBufferEnd = false) noexcept;
 
         void
         _moveEndpointByUnitWord(_In_ const int moveCount,
@@ -178,13 +179,13 @@ namespace Microsoft::Console::Types
         _moveEndpointByUnitLine(_In_ const int moveCount,
                                 _In_ const TextPatternRangeEndpoint endpoint,
                                 _Out_ gsl::not_null<int*> const pAmountMoved,
-                                _In_ const bool preventBufferEnd = false);
+                                _In_ const bool preventBufferEnd = false) noexcept;
 
         void
         _moveEndpointByUnitDocument(_In_ const int moveCount,
                                     _In_ const TextPatternRangeEndpoint endpoint,
                                     _Out_ gsl::not_null<int*> const pAmountMoved,
-                                    _In_ const bool preventBufferEnd = false);
+                                    _In_ const bool preventBufferEnd = false) noexcept;
 
 #ifdef UNIT_TESTING
         friend class ::UiaTextRangeTests;