People collecting their pensions at Meenlaragh Post office in Magheraroarty, West Donegal were told the shocking news today.
Some post office users will now have to travel another five miles to the next nearest post office in Gortahork.
The closure is the second such closure in recent months.
Laghey Post Office outside Donegal Town also closed suddenly and An Post confirmed it will not open again.
Post Mistress at Magheraroarty PO, Ms Mary McFadden, was forced to tell her customers that her office will be closing soon.
One local pensioner told Donegaldaily.com that she was shocked to hear the news.
“I live close to the post office. I don’t drive and I don’t have anybody to drive me.
“I will now have to make arrangements to travel to Gortahork everytime I have to collect my pension or even want to post a letter,” she said.