Orange Order Grand Master of Ireland, Edward Stevenson, joined thousands of people at the Dungannon parade and said: "There is nothing better for a Tyrone Orangeman than to walk on the Twelfth day in the familiar surroundings of his home county."
Sovereign Grand Master of the Royal Black Institution, Millar Farr, and Grand Mistress of the Association of Loyal Orangewomen of Ireland, Olive Whitten, were also present.
Host district Killyman marked the centenary of the start of the First World War, with participants in period dress heading the parade.
Joining brethren from Killyman were Orangemen from six other districts – Stewartstown, Cookstown, Castlecaulfield, Pomeroy, Coagh and Benburb.
The 70 lodges were accompanied by 50 bands.
Thousands of Orangemen, band members and supporters flocked to the Field at The Lord Northland Memorial Park.
The Grand Master said: "Our thoughts today are very much with the current difficulties facing the institution, most notably the intolerance and lack of respect displayed by nationalists and republicans to our valued traditions.
"We think particularly of the brethren in north Belfast who are not only being denied their civil and religious liberties, but also their basic right to walk along a main arterial route to complete their Twelfth of July parade.
"We are also continually aware of the plight of our brethren at Drumcree and other areas across Northern Ireland, who like at Twaddell, are the victims of an incompetent and secret Parades Commission; whose ludicrous determinations are increasingly influenced by the threat of physical force republicanism.
"This serious situation and stark reality, which we outlined only in the past week in person to the Secretary of State, is not only detrimental to community relations but is also bad for democracy in Northern Ireland.
"That is why the leadership of the institution has been working closely with our unionist political representatives in recent times to develop a strategy for all of us to work together in a renewed campaign to finally get rid of the Parades Commission.
"Orangeism and unionism is acting together like never before, with an unprecedented unity of purpose, as we publicly demonstrate our collective opposition to this failed and discredited body, which is now beyond repair.
"I would once again stress that our actions today as an institution and as a community must be peaceful and lawful at all times.
"Any form of violence harms, rather than strengthens, our cause."
Mr Stevenson said the campaign would continue.
"The one thing republicans fear most is unionist co-operation." The Grand Master said Orangemen from Northern Ireland would be in Edinburgh this year to oppose Scottish independence.