Sarnia is a border town that refines fuel for half the province — the Chemical Valley’s refineries sit right in town — yet its pump prices follow the same wholesale racks as everywhere else, a perennial local grievance. Competition runs along London Road and Exmouth Street through the north end, with Point Edward’s stations by the Blue Water Bridge and Corunna serving the valley to the south.
The Michigan question here mirrors Windsor’s: Port Huron pumps usually post a lower per-litre equivalent on tax alone, but bridge tolls and the exchange rate eat the saving unless you are crossing anyway. For everyone staying on this side, the list below ranks every Sarnia-area station we track by current price, refreshed hourly.