Tens of thousands of Orangemen have taken part in the 12 July celebrations at 18 locations across Northern Ireland.
Several policemen were injured during rioting in Belfast and Portadown overnight.
Five people were injured when rival groups clashed at the Broadway roundabout in Belfast.
Petrol bombs, stones, bottles and other missiles were hurled at police during the violence, which police said was largely nationalist-inspired.
Two men were arrested, one remains in custody and a 26-year-old has already been charged with riotous behaviour and will appear in court later in the month.
Police said that with the help of community representatives the situation was calmed.
In Co Antrim, an Orange Hall was attacked by arsonists in the early hours of this morning.
The hall at Main Street in Rasharkin was targeted shortly before 4am. There was scorch damage to the outside of the building and paint was also thrown at the premises.
Meanwhile, at one of the 12th of July Orange demonstrations, a leading member of the Orange Order has called on the Unionist parties to set aside their personality clashes and instead maximise their influence.
The call was made by Drew Nelson (right), the Grand Master of the Orange Lodge of Ireland, after a parade through Belfast.
The new DUP leader, Peter Robinson, has sent out signals that he would like to mend fences. But the leader of the Ulster Unionist party, Reg Empey, has questioned the sincerity of such sentiments.
Defectors from the UUP helped to make the DUP the dominant party.
Mr Nelson has said the disunity is lowering morale and that it could discourage voters in future elections.
But as he was making his plea, evidence surfaced of an additional split. Supporters of the former DUP member and Euro MP Jim Allister distributed thousands of leaflets at a variety of venues, criticising the DUP for being in government with Sinn Féin.
