Nearly ninety people were arrested during protests in Sasolburg on Sunday, Free State police said.
Constable Peter Kareli said the protest began around 9.30am, when residents came out of a meeting about municipal demarcation.
The residents were apparently unhappy about plans to merge Sasolburg into the Ngwathe Local Municipality, which Parys falls under.
Kareli said the group divided into three, and the crowds began barricading streets, burning tyres and throwing stones at police cars.
Police tried negotiating with the protesters, but to no avail.
Windows were broken and shops were looted.
Kareli said police arrested 48 people in possession of goods looted from the shops.
A further 39 people were arrested for public violence.
The arrested protesters would appear in court soon.
He said that some parts of Zamdela village were without electricity, and protesters were trying to loot from tuck shops there after dark.
Police were keeping watch.