Marking the victory of William of Orange over James II at the Battle of the Boyne, the Twelfth remains one of the largest regular cultural events in the UK.
While the main celebrations are still a few days away, events are already formally underway, with the first parade being held across the Irish border in Co Donegal.
Thousands turned out on Saturday for the Orange Order parade in the seaside village of Rossnowlagh.
The march takes place every year on the Saturday before the Twelfth, with more than 60 Orange lodges participating.
Forty bands from Northern Ireland, plus others from Donegal, Cavan, Monaghan and Leitrim, took part in the event, which was also attended by visitors from America, Canada and Australia.
On the big day, events will take place all across Northern Ireland at 19 locations according to the Orange Order.
Parades will be hosted in Killylea, Ballymena, Carrickfergus, Cloughmills, Ahoghill, Broughshane, Gilford, Newtownards, Ballynahinch, Annalong, Irvinestown, Londonderry, Moneymore, Benburb, Newtownstewart, Ballygawley and Derriaghy — with the main parade in Belfast.
This year’s route will continue along its usual 10-mile walk this year with over 70 bands taking part.
The parade is set to begin from Belfast Orange Hall, at Carlisle Circus, at 10am shortly after a wreath-laying ceremony at Belfast City Hall.
Mark Jamison (left) and Mark Gibson take a selfie on the beach after the annual Orange Order parade in Rossnowlagh
The return parade is due to leave Barnett’s Demesne and proceed towards the city centre at 3.30pm.
In addition to the parade in Belfast, the city centre will also be hosting ‘Orangefest’, which launched in 2007.
Kicking off at 9am, it includes a line-up from an international food market in the grounds of City Hall organised by Food NI and Taste of Ulster, offering up a range of local and international cuisines, as well as live cooking demonstrations.
Circus and street entertainers will also be performing street theatre on the grounds, where stilt walkers, drumming workshops from community drummers, drop-in circus skills and circus shows will all be provided for free and will be suitable for all ages.
In addition to Orangefest, various communities across Northern Ireland are holding funfairs, barbecues and events to honour the day.
In Newtownards, attendees can expect entertainment with Irish and Scottish dancers, as well as a small re-enactment which will be recreating the Battle of the Boyne in Londonderry Park, while Killylea will hold the largest gathering of the day, with over 150 lodges expected.
The festivities in Ballynahinch will also feature refreshments and a service in the demonstration field from 2pm, while the return parade will leave at around 4pm following the same route.
Just ahead of the Twelfth, revellers in Craigyhill in Larne will be lighting what could well be the world’s largest bonfire.
The structure is currently over 300 pallets high and is now on track to surpass last year’s height.
Thousands gathered for the annual Orange Order parade in Rossnowlagh
It’s set to be lit at midnight on the Eleventh Night, with funds being raised for two local families.
On the 13th of July, tens of thousands are expected at the annual ‘sham fight’ in Scarva, Co Down.
The annual ‘fight’ features a re-enactment of the Battle of the Boyne, between rival monarchs William and James alongside a large procession.
This year’s event will feature nine visiting preceptories, including visitors from Australia and New Zealand, who will join the parade of 4,000 members of the Royal Black Institution and around 85 bands.
As for the weather for the day itself, the Met Office has predicted a “few sporadic showers” with some “sunny spells”.
The PSNI has advised motorists that some “traffic disruption” is to be expected due to the parades planned throughout the day.
Officers will be on the ground to accommodate the flow of traffic in all locations on the day and to avoid potential delays.