diff --git a/netbox/ipam/models/ip.py b/netbox/ipam/models/ip.py
index b38f04ecc..e96fe7806 100644
--- a/netbox/ipam/models/ip.py
+++ b/netbox/ipam/models/ip.py
@@ -408,8 +408,6 @@ class Prefix(ContactsMixin, GetAvailablePrefixesMixin, CachedScopeMixin, Primary
         """
         Return all available IPs within this prefix as an IPSet.
         """
-        # TODO: Add mark_populated
-
         prefix = netaddr.IPSet(self.prefix)
         child_ips = netaddr.IPSet([
             ip.address.ip for ip in self.get_child_ips()
@@ -889,6 +887,20 @@ class IPAddress(ContactsMixin, PrimaryModel):
                         )
                     })
 
+            # Disallow the creation of IPAddresses within an IPRange with mark_populated=True
+            parent_range = IPRange.objects.filter(
+                start_address__lte=self.address,
+                end_address__gte=self.address,
+                vrf=self.vrf,
+                mark_populated=True
+            ).first()
+            if parent_range:
+                raise ValidationError({
+                    'address': _(
+                        "Cannot create IP address {ip} inside range {range}."
+                    ).format(ip=self.address, range=parent_range)
+                })
+
         if self._original_assigned_object_id and self._original_assigned_object_type_id:
             parent = getattr(self.assigned_object, 'parent_object', None)
             ct = ObjectType.objects.get_for_id(self._original_assigned_object_type_id)
diff --git a/netbox/ipam/tests/test_models.py b/netbox/ipam/tests/test_models.py
index f41c93539..246ca0e22 100644
--- a/netbox/ipam/tests/test_models.py
+++ b/netbox/ipam/tests/test_models.py
@@ -582,6 +582,27 @@ class TestIPAddress(TestCase):
         IPAddress.objects.create(address=IPNetwork('192.0.2.1/24'), role=IPAddressRoleChoices.ROLE_VIP)
         IPAddress.objects.create(address=IPNetwork('192.0.2.1/24'), role=IPAddressRoleChoices.ROLE_VIP)
 
+    #
+    # Range validation
+    #
+
+    def test_create_ip_in_unpopulated_range(self):
+        IPRange.objects.create(
+            start_address=IPNetwork('192.0.2.1/24'),
+            end_address=IPNetwork('192.0.2.100/24')
+        )
+        ip = IPAddress(address=IPNetwork('192.0.2.10/24'))
+        ip.full_clean()
+
+    def test_create_ip_in_populated_range(self):
+        IPRange.objects.create(
+            start_address=IPNetwork('192.0.2.1/24'),
+            end_address=IPNetwork('192.0.2.100/24'),
+            mark_populated=True
+        )
+        ip = IPAddress(address=IPNetwork('192.0.2.10/24'))
+        self.assertRaises(ValidationError, ip.full_clean)
+
 
 class TestVLANGroup(TestCase):