More than 10,1000 protestors were involved in disorder in Blackpool, following the misinformation of stabbings that took place in Southport.
Police struggled to contain demonstrators, who were mainly from far-right groups, in the seaside town.
People gathered near the town’s cenotaph before proceeding through the streets. Bottles and planks of wood were thrown and racist gestures were made.
A counter-protest was help by people attending the local Rebellion punk festival.
Lancashire Police confirmed there had also been protests in Preston and Blackburn and it had introduced dispersal orders in all three areas.
The force said it had made more than 20″ arrests across the county in connection with the protests, with people being held on suspicion of possession of an offensive weapon, police assault, possession of a bladed article, obstructing police, conspiracy to commit violent disorder and failing to adhere to a dispersal order.
Blackpool South MP Chris Webb said he was angered to see senseless violence and disorder on the streets of his hometown.
The protests followed the deaths of three young girls who died after being stabbed on Monday.
False claims had spread online that the person responsible for their deaths was an asylum seeker, and a Muslim.
British-born Axel Muganwa Rudakubana (17), from Banks in Lancashire, has been charged with three counts of murder, 10 attempted murders and possession of a curved kitchen knife. He has no known links to Islam.
