Protesters carrying banners and placards besieged the council offices in Carmarthen on Wednesday, calling for village schools to remain open.
Representatives from Llanedi, one of the primary schools threatened with closure, then presented a 250-name petition to a council meeting.
Helen Slee, 43, whose eight-year-old daughter Rachel attends Llanedi, said:
"Our school is at the centre of an up-and-coming community. We do not believe a larger school can offer better facilities."
The authority unveiled a pound;110 million spending plan for education in October. It plans to build one new secondary and 19 new primaries, to ensure that all pupils have access to modern school buildings and facilities. But parents fear that up to a quarter of Carmarthenshire's 133 existing primaries will close as a result.
Protester Nia Evans, whose children attend Rhydcymerau primary, which is threatened with closure, said: "The heart will be ripped out of our community."
But Alun Davies, Carmarthenshire director of lifelong learning, said: "This programme represents a huge investment for a better, all-round education for every child in Carmarthenshire. But we will not be deciding the future of any of our schools this week."