Parents and children in Carmarthenshire have staged a rally outside a 13-pupil school that could shut by the end of the year.
Campaigners say children will have to be bussed to other schools
They are fighting cuts that the council says are caused by 5,000 spare places at its primary schools.
Earlier this month senior councillors backed plans to close Mynyddcerrig in the Gwendraeth Valley.
Campaigners said they would "take a stand" at the school because if it closed others would soon follow.
Carmarthenshire Council has a 10-year programme aimed at reducing surplus places and improving school buildings that could see up to 32 schools closed and replaced with new area "super schools".
Other Welsh councils are also reviewing schools in the wake of spare places.
On Thursday opposition parties on Cardiff Council rejected a consultation proposed by the Liberal Democrat-led administration for the closure of 17 city schools.
The head teacher at Mynyddcerrig recently retired and the school was put into special measures last year after an Estyn inspection.
But parents said their children would have to be bussed to other schools as there were none within walking distance.
The council says it cannot afford to maintain surplus school places
Among the speakers were representatives from Cymdeithas yr Iaith Gymraeg (Welsh Language Society) and the Carmarthenshire Primary Schools Forum.
Cymdeithas education spokesman Ffred Ffrancis said: "The council could have followed the lead of Cardiff Council and put their whole strategy out for county-wide consultation before starting to take out individual schools.
"They could have worked with local people who feel passionately for the education of their children and for the future of their communities rather than slapping them down."
Carmarthenshire Council said it would consult with staff, parents and governors.
It said it could no longer afford to keep 5,000 surplus places in the county and buildings at many of the schools that would be affected by its modernising education programme were not suitable for the 21st Century.
The council said it had pledged £110m over the next 10 years for improvements, but in some cases that would create area schools in place of small village ones.