For the most part, the parades and gatherings afterward were peaceful, the BBC said.
About 100 protesters gathered at one march with signs reading, "No Talk, No Walk."
Democratic Unionist North Belfast MP Nigel Dodds said he was glad the marches were not disrupted by violence.
Sinn Fein's Gerry Kelly echoed the sentiment, but added he hoped the peace would hold up as the day wears, "especially if there is drink taken."
Before the parades in Belfast, vandals damaged a memorial dedicated to five people killed in a 1992 shooting spree. Officials said they were looking to stir up tensions.