The deployment template provides variables to set defaults. One of the variables is default_region which defines the default region to create resources. By setting the default to Montreal which is northamerica-northeast1 then the resource creation will be restricted to only that region. For details on the template please see Bootstrap Template
You can also choose to provide an Organization Policy which would restrict any future resource creation for the entire organization. You can find details on this option here Restricting Resource Location
The validation template will search the entire Cloud Asset Inventory for any resources that are not located on the default region