diff --git a/app/code/Magento/Checkout/view/frontend/web/js/model/new-customer-address.js b/app/code/Magento/Checkout/view/frontend/web/js/model/new-customer-address.js
index 22e03c86f5d0a..7b858c92bee34 100644
--- a/app/code/Magento/Checkout/view/frontend/web/js/model/new-customer-address.js
+++ b/app/code/Magento/Checkout/view/frontend/web/js/model/new-customer-address.js
@@ -26,7 +26,7 @@ define([
             if (addressData.region && addressData.region['region_id']) {
                 regionId = addressData.region['region_id'];
             } else if (!addressData['region_id']) {
-                regionId = null;
+                regionId = undefined;
             } else if (countryId === window.checkoutConfig.defaultCountryId) {
                 regionId = window.checkoutConfig.defaultRegionId;
             }