Do I need a new eManifest each time I make a crossing?

Yes. For entry into the United States or Canada, both CBP and CBSA require a new ACE or ACI eManifest submission. Each eManifest includes a unique Trip Number that identifies the eManifest and can thus only be used once. After ‘arriving’ at the border, an ACE or ACI eManifest is considered closed. As well, when you are transporting commercial goods across the border, the eManifest will include information specific to that shipment (including the PAPS/PARS number(s)).  This allows the eManifest to be matched with the customs broker’s documentation.  Once that cargo has arrived at the border, the PAPS/PARS number cannot be resubmitted.  Similarly, the Trip Number cannot be reused.  Therefore, a new eManifest with a new, unused Trip Number (and PAPS/PARS number(s) when applicable) needs to be obtained for each crossing.