diff --git a/netbox/dcim/api/serializers.py b/netbox/dcim/api/serializers.py
index 3c4021e72..83e0fb271 100644
--- a/netbox/dcim/api/serializers.py
+++ b/netbox/dcim/api/serializers.py
@@ -123,7 +123,7 @@ class SiteSerializer(PrimaryModelSerializer):
     class Meta:
         model = Site
         fields = [
-            'id', 'url', 'display', 'name', 'slug', 'status', 'region', 'group', 'tenant', 'facility', 'asns',
+            'id', 'url', 'display', 'name', 'slug', 'status', 'region', 'group', 'tenant', 'facility', 'asn', 'asns',
             'time_zone', 'description', 'physical_address', 'shipping_address', 'latitude', 'longitude', 'contact_name',
             'contact_phone', 'contact_email', 'comments', 'tags', 'custom_fields', 'created', 'last_updated',
             'asn_count', 'circuit_count', 'device_count', 'prefix_count', 'rack_count', 'virtualmachine_count',
diff --git a/netbox/dcim/filtersets.py b/netbox/dcim/filtersets.py
index 82396b64b..0142b36c6 100644
--- a/netbox/dcim/filtersets.py
+++ b/netbox/dcim/filtersets.py
@@ -163,6 +163,7 @@ class SiteFilterSet(PrimaryModelFilterSet, TenancyFilterSet):
             Q(comments__icontains=value)
         )
         try:
+            qs_filter |= Q(asn=int(value.strip()))
             qs_filter |= Q(asns=int(value.strip()))
         except ValueError:
             pass
diff --git a/netbox/dcim/forms/models.py b/netbox/dcim/forms/models.py
index 9703c4cac..805788c04 100644
--- a/netbox/dcim/forms/models.py
+++ b/netbox/dcim/forms/models.py
@@ -122,13 +122,14 @@ class SiteForm(BootstrapMixin, TenancyForm, CustomFieldModelForm):
     class Meta:
         model = Site
         fields = [
-            'name', 'slug', 'status', 'region', 'group', 'tenant_group', 'tenant', 'facility', 'asns', 'time_zone',
-            'description', 'physical_address', 'shipping_address', 'latitude', 'longitude', 'contact_name',
+            'name', 'slug', 'status', 'region', 'group', 'tenant_group', 'tenant', 'facility', 'asn', 'asns',
+            'time_zone', 'description', 'physical_address', 'shipping_address', 'latitude', 'longitude', 'contact_name',
             'contact_phone', 'contact_email', 'comments', 'tags',
         ]
         fieldsets = (
             ('Site', (
-                'name', 'slug', 'status', 'region', 'group', 'facility', 'asns', 'time_zone', 'description', 'tags',
+                'name', 'slug', 'status', 'region', 'group', 'facility', 'asn', 'asns', 'time_zone', 'description',
+                'tags',
             )),
             ('Tenancy', ('tenant_group', 'tenant')),
             ('Contact Info', (
@@ -152,6 +153,7 @@ class SiteForm(BootstrapMixin, TenancyForm, CustomFieldModelForm):
         }
         help_texts = {
             'name': "Full name of the site",
+            'asn': "BGP autonomous system number.  This field is depreciated in favour of the many-to-many field for ASNs",
             'facility': "Data center provider and facility (e.g. Equinix NY7)",
             'time_zone': "Local time zone",
             'description': "Short description (will appear in sites list)",
@@ -161,6 +163,18 @@ class SiteForm(BootstrapMixin, TenancyForm, CustomFieldModelForm):
             'longitude': "Longitude in decimal format (xx.yyyyyy)"
         }
 
+    def __init__(self, instance, *args, **kwargs):
+        super(SiteForm, self).__init__(instance=instance, *args, **kwargs)
+        if instance is None or (instance and (instance.asn is None or instance.asn == '')):
+            site_fieldset = list(self.Meta.fieldsets[0][1])
+            site_fieldset.pop(6)
+            self.Meta.fieldsets = (
+                ('Site', tuple(site_fieldset)),
+                self.Meta.fieldsets[1],
+                self.Meta.fieldsets[2],
+            )
+            del self.fields['asn']
+
 
 class LocationForm(BootstrapMixin, TenancyForm, CustomFieldModelForm):
     region = DynamicModelChoiceField(
diff --git a/netbox/dcim/migrations/0138_remove_site_asn.py b/netbox/dcim/migrations/0138_remove_site_asn.py
deleted file mode 100644
index a4100ea14..000000000
--- a/netbox/dcim/migrations/0138_remove_site_asn.py
+++ /dev/null
@@ -1,18 +0,0 @@
-# Generated by Django 3.2.8 on 2021-10-25 04:33
-
-from django.db import migrations
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('dcim', '0137_relax_uniqueness_constraints'),
-        ('ipam', '0051_asn_model')
-    ]
-
-    operations = [
-        migrations.RemoveField(
-            model_name='site',
-            name='asn',
-        ),
-    ]
diff --git a/netbox/dcim/models/sites.py b/netbox/dcim/models/sites.py
index a093a4d84..ab9d8e82d 100644
--- a/netbox/dcim/models/sites.py
+++ b/netbox/dcim/models/sites.py
@@ -189,6 +189,12 @@ class Site(PrimaryModel):
         blank=True,
         help_text='Local facility ID or description'
     )
+    asn = ASNField(
+        blank=True,
+        null=True,
+        verbose_name='ASN',
+        help_text='32-bit autonomous system number'
+    )
     time_zone = TimeZoneField(
         blank=True
     )
@@ -251,7 +257,7 @@ class Site(PrimaryModel):
     objects = RestrictedQuerySet.as_manager()
 
     clone_fields = [
-        'status', 'region', 'group', 'tenant', 'facility', 'time_zone', 'description', 'physical_address',
+        'status', 'region', 'group', 'tenant', 'facility', 'asn', 'time_zone', 'description', 'physical_address',
         'shipping_address', 'latitude', 'longitude', 'contact_name', 'contact_phone', 'contact_email',
     ]
 
diff --git a/netbox/templates/dcim/site.html b/netbox/templates/dcim/site.html
index 55cc57b50..260412815 100644
--- a/netbox/templates/dcim/site.html
+++ b/netbox/templates/dcim/site.html
@@ -80,6 +80,10 @@
                         <th scope="row">Description</th>
                         <td>{{ object.description|placeholder }}</td>
                     </tr>
+                    <tr>
+                        <th scope="row">AS Number</th>
+                        <td>{{ object.asn|placeholder }}</td>
+                    </tr>
                     <tr>
                         <th scope="row">Time Zone</th>
                         <td>