For much of the route along quiet country roads the only spectators were cows and sheep, but that changed as the procession neared the village.
There was a festival atmosphere as people lined the roads in the sunshine, many enjoying picnics.
Further into the village spectators were six rows deep and clapped politely as bands and members from Donegal, Cavan, Leitrim and Monaghan, joined by lodges from Fermanagh, Derry, Antrim and Armagh, strolled by.
Many spectators, perhaps more accustomed to the marches over the border, remarked how relaxed the affair was. The security operation was certainly more laidback.
Fewer than five Garda officers in shirt sleeves laughed and joked with passers-by as they directed traffic.
East Belfast woman Helen Joy said: "This is our first visit ever. It is really fabulous, it is so relaxed.
"Compared to the Belfast one, it is really chilled out, there is loads of room and it's so clean. It's lovely.
"We love Scarva too, which is very like Rossnowlagh. We call it the grown-up Twelfth and this is that too.
"The Belfast Twelfth is quite mad and busy and 'blood and thunder'. Here there are pipe bands and brass bands and accordion bands, just a lovely mix of everything."
The walking done, the bands piled into the demonstration field. Some spectators, who had found themselves a comfy spot in the long grass for a snooze, were awoken by the arrival of the Red Hand Defenders Flute Band from Newtownstewart.
Band leader Sam Allison said they hadn't been to Rossnowlagh in over 30 years.
"We were always a 'blood and thunder' band. We won't be changing," he said.
"The Donegal air hasn't mellowed us out at all.
"We enjoy that brand of stuff. There are 21 fluters, 12 drummers and two big bass drums. I hope we will get invited back next year."
One lodge especially happy to be in attendance was Donegal's Newtowncunningham.
Its hall, not far from the Derry/Donegal border and dating back to 1911, was burnt down in an arson attack in September 2014.
This is the first year since then that members have been able to leave for the Rossnowlagh parade from their rebuilt home.
Newtowncunningham Orangeman John Boreland said the arsonists had failed to intimidate the lodge.
He said: "The blaze destroyed our building completely, but we came back here the year after. We were not beaten by it.
"We decided that instead of going that way we would go the opposite way and stand up and be seen.
"And the support we got from the other brethren was unbelievable.
"We opened in September of last year so this is our first Donegal Twelfth with our new hall in operation.
"It's amazing to be back here and to be able to thank people for all the support.
"The neighbouring lodges gave us their halls for our band practice and lodge meetings.
"It is just good now to get home and leave to come here from your own home instead of someone else's."
John said that despite the arsonists' intention to shut them down, the Newtowncunningham lodge is thriving.
"It really backfired on them because we have become stronger," he added.
Alan Mackarel, county secretary of the Monaghan LOL, said he sees a distinct difference between Orangemen depending what side of the border they came from.
"I think the order is a bit different here than in the north. We go for a walk, they'd be here for a march," he said.
"South of the border, today is a more family-orientated day out, dare I say it, less hardline. But then those north of the border had it tougher and that maybe makes them hardline. There are some blood and thunder bands here today, but again they are the north elements."
And for many of the northern brethren, experiencing the relaxed atmosphere at Rossnowlagh has left them longing for the same.
Johnny Harvey from Pride of Ballymacarrett Temperance LOL 1075 said: "This is what a parade should be like. It is a nice, peaceful day out. Everyone is enjoying it, loving the sunshine and celebrations, having a good day. And you can see that there are people from different backgrounds out enjoying it, which is nice.
"The pace here is definitely a bit more laidback compared to Belfast. We had to walk a lot slower. It is much more relaxed.
"I think that is what it should be like in Belfast. I think that if we didn't have the opposition in the north, this is what it would be like, if we were allowed to have it this way."