diff --git a/CHANGES.md b/CHANGES.md
index 8acf88d28bfc..80d08c4616e9 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -11,6 +11,7 @@ Change Log
 * Fixed a bug affected models with multiple meshes without indices. [#4237](https://github.com/AnalyticalGraphicsInc/cesium/issues/4237)
 * Fixed a glTF transparency bug where `blendFuncSeparate` parameters were loaded in the wrong order. [#4435](https://github.com/AnalyticalGraphicsInc/cesium/pull/4435)
 * Fixed a bug where creating a custom geometry with attributes and indices that have values that are not a typed array would cause a crash. [#4419](https://github.com/AnalyticalGraphicsInc/cesium/pull/4419)
+* `KmlDataSource` and `GeoJsonDataSource` were not honoring the `clampToGround` option for billboards and labels and was instead always clamping, reducing performance in cases when it was unneeded.
 * Fixed a bug with rotated, textured rectangles. [#4430](https://github.com/AnalyticalGraphicsInc/cesium/pull/4430)
 * Fixed a bug when morphing from 2D to 3D. [#4388](https://github.com/AnalyticalGraphicsInc/cesium/pull/4388)
 * Fixed a bug where when KML features had duplicate IDs, only one was drawn. [#3941](https://github.com/AnalyticalGraphicsInc/cesium/issues/3941)
diff --git a/Source/DataSources/GeoJsonDataSource.js b/Source/DataSources/GeoJsonDataSource.js
index bdae9dfa8315..637cdf7d50a7 100644
--- a/Source/DataSources/GeoJsonDataSource.js
+++ b/Source/DataSources/GeoJsonDataSource.js
@@ -285,7 +285,7 @@ define([
         billboard.verticalOrigin = new ConstantProperty(VerticalOrigin.BOTTOM);
 
         // Clamp to ground if there isn't a height specified
-        if (coordinates.length === 2) {
+        if (coordinates.length === 2 && options.clampToGround) {
             billboard.heightReference = HeightReference.CLAMP_TO_GROUND;
         }
 
diff --git a/Source/DataSources/KmlDataSource.js b/Source/DataSources/KmlDataSource.js
index eed05c7ff8d8..8ad8ff9e4cb1 100644
--- a/Source/DataSources/KmlDataSource.js
+++ b/Source/DataSources/KmlDataSource.js
@@ -1089,7 +1089,7 @@ define([
             }
         }
 
-        if (defined(heightReference)) {
+        if (defined(heightReference) && dataSource._clampToGround) {
             billboard.heightReference = heightReference;
             label.heightReference = heightReference;
         }
diff --git a/Specs/DataSources/KmlDataSourceSpec.js b/Specs/DataSources/KmlDataSourceSpec.js
index 24ac384f943b..c5a467b1eb86 100644
--- a/Specs/DataSources/KmlDataSourceSpec.js
+++ b/Specs/DataSources/KmlDataSourceSpec.js
@@ -2192,7 +2192,7 @@ defineSuite([
         });
     });
 
-    it('Geometry Point: sets heightReference to clampToGround (the default)', function() {
+    it('Geometry Point: sets heightReference to clampToGround', function() {
         var kml = '<?xml version="1.0" encoding="UTF-8"?>\
           <Placemark>\
             <Point>\
@@ -2200,7 +2200,11 @@ defineSuite([
             </Point>\
           </Placemark>';
 
-        return KmlDataSource.load(parser.parseFromString(kml, "text/xml"), options).then(function(dataSource) {
+        return KmlDataSource.load(parser.parseFromString(kml, "text/xml"), {
+            camera : options.camera,
+            canvas : options.canvas,
+            clampToGround : true
+        }).then(function(dataSource) {
             var entities = dataSource.entities.values;
             expect(entities.length).toEqual(1);
             expect(entities[0].billboard.heightReference.getValue(Iso8601.MINIMUM_VALUE)).toEqual(HeightReference.CLAMP_TO_GROUND);
@@ -2705,7 +2709,7 @@ defineSuite([
         });
     });
 
-    it('Geometry gx:Track: sets position and availability (clampToGround default)', function() {
+    it('Geometry gx:Track: sets position and availability', function() {
         var kml = '<?xml version="1.0" encoding="UTF-8"?>\
             <Placemark xmlns="http://www.opengis.net/kml/2.2"\
                        xmlns:gx="http://www.google.com/kml/ext/2.2">\
@@ -2719,7 +2723,11 @@ defineSuite([
               </gx:Track>\
             </Placemark>';
 
-        return KmlDataSource.load(parser.parseFromString(kml, "text/xml"), options).then(function(dataSource) {
+        return KmlDataSource.load(parser.parseFromString(kml, "text/xml"), {
+            camera : options.camera,
+            canvas : options.canvas,
+            clampToGround : true
+        }).then(function(dataSource) {
             var time1 = JulianDate.fromIso8601('2000-01-01T00:00:00Z');
             var time2 = JulianDate.fromIso8601('2000-01-01T00:00:01Z');
             var time3 = JulianDate.fromIso8601('2000-01-01T00:00:02Z');
@@ -2754,7 +2762,11 @@ defineSuite([
               </gx:Track>\
             </Placemark>';
 
-        return KmlDataSource.load(parser.parseFromString(kml, "text/xml"), options).then(function(dataSource) {
+        return KmlDataSource.load(parser.parseFromString(kml, "text/xml"), {
+            camera : options.camera,
+            canvas : options.canvas,
+            clampToGround : true
+        }).then(function(dataSource) {
             var time1 = JulianDate.fromIso8601('2000-01-01T00:00:00Z');
             var time2 = JulianDate.fromIso8601('2000-01-01T00:00:01Z');
             var time3 = JulianDate.fromIso8601('2000-01-01T00:00:02Z');
@@ -2847,7 +2859,11 @@ defineSuite([
                 </gx:Track>\
           </Placemark>';
 
-        return KmlDataSource.load(parser.parseFromString(kml, "text/xml"), options).then(function(dataSource) {
+        return KmlDataSource.load(parser.parseFromString(kml, "text/xml"), {
+            camera : options.camera,
+            canvas : options.canvas,
+            clampToGround : true
+        }).then(function(dataSource) {
             var time1 = JulianDate.fromIso8601('2000-01-01T00:00:00Z');
             var time2 = JulianDate.fromIso8601('2000-01-01T00:00:01Z');
             var time3 = JulianDate.fromIso8601('2000-01-01T00:00:02Z');