diff --git a/django/contrib/gis/geos/collections.py b/django/contrib/gis/geos/collections.py
index 7427a4569f7..4935dbd1c3c 100644
--- a/django/contrib/gis/geos/collections.py
+++ b/django/contrib/gis/geos/collections.py
@@ -3,7 +3,6 @@
  GeometryCollection, MultiPoint, MultiLineString, and MultiPolygon
 """
 import json
-import warnings
 from ctypes import byref, c_int, c_uint
 
 from django.contrib.gis.geos import prototypes as capi
@@ -13,7 +12,6 @@ from django.contrib.gis.geos.libgeos import geos_version_info, get_pointer_arr
 from django.contrib.gis.geos.linestring import LinearRing, LineString
 from django.contrib.gis.geos.point import Point
 from django.contrib.gis.geos.polygon import Polygon
-from django.utils.deprecation import RemovedInDjango20Warning
 from django.utils.six.moves import range
 
 
@@ -128,15 +126,6 @@ class MultiPolygon(GeometryCollection):
     _allowed = Polygon
     _typeid = 6
 
-    @property
-    def cascaded_union(self):
-        "Returns a cascaded union of this MultiPolygon."
-        warnings.warn(
-            "`cascaded_union` is deprecated, use the `unary_union` property instead.",
-            RemovedInDjango20Warning, 2
-        )
-        return GEOSGeometry(capi.geos_cascaded_union(self.ptr), self.srid)
-
 
 # Setting the allowed types here since GeometryCollection is defined before
 # its subclasses.
diff --git a/django/contrib/gis/geos/prototypes/topology.py b/django/contrib/gis/geos/prototypes/topology.py
index b2cf0681a8d..f8c36bc6f57 100644
--- a/django/contrib/gis/geos/prototypes/topology.py
+++ b/django/contrib/gis/geos/prototypes/topology.py
@@ -33,7 +33,6 @@ geos_simplify = Topology('GEOSSimplify', argtypes=[GEOM_PTR, c_double])
 geos_symdifference = Topology('GEOSSymDifference', argtypes=[GEOM_PTR, GEOM_PTR])
 geos_union = Topology('GEOSUnion', argtypes=[GEOM_PTR, GEOM_PTR])
 
-geos_cascaded_union = GEOSFuncFactory('GEOSUnionCascaded', argtypes=[GEOM_PTR], restype=GEOM_PTR)
 geos_unary_union = GEOSFuncFactory('GEOSUnaryUnion', argtypes=[GEOM_PTR], restype=GEOM_PTR)
 
 # GEOSRelate returns a string, not a geometry.
diff --git a/docs/ref/contrib/gis/geos.txt b/docs/ref/contrib/gis/geos.txt
index 165f3c07541..b92a91491ab 100644
--- a/docs/ref/contrib/gis/geos.txt
+++ b/docs/ref/contrib/gis/geos.txt
@@ -839,17 +839,6 @@ Geometry Collections
         In previous versions, an empty ``MultiPolygon`` couldn't be
         instantiated.
 
-    .. attribute:: cascaded_union
-
-        .. deprecated:: 1.10
-
-            Use the :attr:`GEOSGeometry.unary_union` property instead.
-
-        Returns a :class:`Polygon` that is the union of all of the component
-        polygons in this collection.  The algorithm employed is significantly
-        more efficient (faster) than trying to union the geometries together
-        individually. [#fncascadedunion]_
-
 ``GeometryCollection``
 ----------------------
 
@@ -1142,7 +1131,6 @@ include the SRID value (in other words, EWKB).
 
 .. rubric:: Footnotes
 .. [#fnogc] *See* `PostGIS EWKB, EWKT and Canonical Forms <http://postgis.net/docs/using_postgis_dbmanagement.html#EWKB_EWKT>`_, PostGIS documentation at Ch. 4.1.2.
-.. [#fncascadedunion] For more information, read Paul Ramsey's blog post about `(Much) Faster Unions in PostGIS 1.4 <http://blog.cleverelephant.ca/2009/01/must-faster-unions-in-postgis-14.html>`_ and Martin Davis' blog post on `Fast polygon merging in JTS using Cascaded Union <http://lin-ear-th-inking.blogspot.com/2007/11/fast-polygon-merging-in-jts-using.html>`_.
 
 Settings
 ========
diff --git a/docs/releases/2.0.txt b/docs/releases/2.0.txt
index 6025e7de881..0bc5c8d388a 100644
--- a/docs/releases/2.0.txt
+++ b/docs/releases/2.0.txt
@@ -333,3 +333,6 @@ these features.
 
 * The ``get_coords()`` and ``set_coords()`` methods of
   ``django.contrib.gis.geos.Point`` are removed.
+
+* The ``cascaded_union`` property of ``django.contrib.gis.geos.MultiPolygon``
+  is removed.
diff --git a/tests/gis_tests/geos_tests/test_geos.py b/tests/gis_tests/geos_tests/test_geos.py
index 4ee3c7309a3..46583c9605a 100644
--- a/tests/gis_tests/geos_tests/test_geos.py
+++ b/tests/gis_tests/geos_tests/test_geos.py
@@ -18,9 +18,8 @@ from django.contrib.gis.geos.libgeos import geos_version_info
 from django.contrib.gis.shortcuts import numpy
 from django.template import Context
 from django.template.engine import Engine
-from django.test import SimpleTestCase, ignore_warnings, mock
+from django.test import SimpleTestCase, mock
 from django.utils import six
-from django.utils.deprecation import RemovedInDjango20Warning
 from django.utils.encoding import force_bytes
 from django.utils.six.moves import range
 
@@ -1315,9 +1314,3 @@ class GEOSTest(SimpleTestCase, TestDataMixin):
         self.assertEqual(p.transform(2774, clone=True), Point(srid=2774))
         p.transform(2774)
         self.assertEqual(p, Point(srid=2774))
-
-    @ignore_warnings(category=RemovedInDjango20Warning)
-    def test_deprecated_cascaded_union(self):
-        for geom in self.geometries.multipolygons:
-            mpoly = GEOSGeometry(geom.wkt)
-            self.assertEqual(mpoly.cascaded_union, mpoly.unary_union)