diff --git a/src/applications/metamta/adapter/PhabricatorMailMailgunAdapter.php b/src/applications/metamta/adapter/PhabricatorMailMailgunAdapter.php
--- a/src/applications/metamta/adapter/PhabricatorMailMailgunAdapter.php
+++ b/src/applications/metamta/adapter/PhabricatorMailMailgunAdapter.php
@@ -24,6 +24,7 @@
       array(
         'api-key' => 'string',
         'domain' => 'string',
+        'api-hostname' => 'string',
       ));
   }
 
@@ -31,12 +32,14 @@
     return array(
       'api-key' => null,
       'domain' => null,
+      'api-hostname' => 'api.mailgun.net',
     );
   }
 
   public function sendMessage(PhabricatorMailExternalMessage $message) {
     $api_key = $this->getOption('api-key');
     $domain = $this->getOption('domain');
+    $api_hostname = $this->getOption('api-hostname');
     $params = array();
 
     $subject = $message->getSubject();
@@ -92,7 +95,8 @@
     }
 
     $mailgun_uri = urisprintf(
-      'https://api.mailgun.net/v2/%s/messages',
+      'https://%s/v2/%s/messages',
+      $api_hostname,
       $domain);
 
     $future = id(new HTTPSFuture($mailgun_uri, $params))
diff --git a/src/docs/user/configuration/configuring_outbound_email.diviner b/src/docs/user/configuration/configuring_outbound_email.diviner
--- a/src/docs/user/configuration/configuring_outbound_email.diviner
+++ b/src/docs/user/configuration/configuring_outbound_email.diviner
@@ -227,6 +227,9 @@
 
   - `api-key`: Required string. Your Mailgun API key.
   - `domain`: Required string. Your Mailgun domain.
+  - `api-hostname`: Optional string. Defaults to "api.mailgun.net". If your
+    account is in another region (like the EU), you may need to specify a
+    different hostname. Consult the Mailgun documentation.
 
 
 Mailer: Amazon SES