Canada Post will begin reviewing public comments about its proposal to close the historical Olde Sandwich Town post office.
A 30-day notice asking for reaction has come to an end.
Rallies have been held to save the post office at the intersection of Sandwich and Mill streets on the city's west-end.
Jeff Carrol, president of the local branch of the postal workers' union, said he feels good about the public support.
"I think we had a good showing. They really need to keep it open," he said. "There's a lot of seniors in that end of town. It's an important part of that community, so we're thinking positive here."
In the meantime, Canada Post is proceeding with plans for its mail sorting operation on Walker Road.
Carrol said Sunday is the last day mail will be mechanically sorted at the outlet.
After this weekend, the plant will focus on parcels and direct marketing mail. Other mail will be sent to London for sorting and delivery:
"Their plan is to move forward and move mechanized mail out of here. There's no backing off on that," Carrol said.
The change will result in the loss of 80 to 100 jobs through attrition and not immediately, Canada Post previously said.