Up to 1,000 EDL members travelled to Dudley to protest against plans for a mosque, amid a heavy police presence.
The protesters marched from the town centre to the council house and held speeches objecting to the so-called "super mosque".
Many shops shut for the afternoon and some were boarded up as a precaution, although the Churchill shopping centre stayed open.
A counter-protest was staged by members of Unite Against Fascism (UAF).
Thirty arrests were made mainly to prevent a breach of the peace, police said.
Maria Jones, of Teddy Grays sweetshop, said her store closed at lunchtime.
"We are worried there will be trouble. There have a been a few shoppers about, but not many," she said.
BBC reporter James Bovill said plenty of shops had remained closed and many had been boarded up.
Dudley Council said there would be a market and free parking in the town next weekend to make up for the disruption.
Peter Lowe, leader of the Labour-led authority, said: "We recognise there will be issues in the community but that will be dealt with by the people of this town.
"What we don't need are outsiders who don't understand the issues that affect Dudley, they come in and spread their hatred and their lies."
One EDL member who travelled from Colchester, Essex, said he was in Dudley to protest against the building of the "super mosque".
Although planning permission is still being dealt with by the courts, he insisted it would go ahead.
"We are not violent, racist thugs, I am not a racist," he said.
"But I don't want my children growing up in a country where Sharia law is allowed."
Weyman Bennett, joint national secretary of Unite Against Fascism, a group which took part in the counter-demonstration, said he was there to stand in solidarity with the people of Dudley.
"It's a very welcoming community, the fact that people can mix together and live together is a positive thing," he said.