By the time the Battle of the Boyne took place on 12 July 1690, the war in Ireland had been going on for a year. King William himself arrived in Belfast in June 1690, with a further 15,000 reinforcements, bringing the strength of his forces to 36,000.
King James had retreated from the North, where he had failed to take either Derry or Enniskillen. If he wanted to hold Dublin, he had to make the River Boyne his line of defence. So by the end of June 1690, James had his 25,000-strong Jacobite army camped by the side of the Boyne. By the time the battle was concluded, about 500 Williamite solders and 1,000 Jacobite men had been killed. William won control over Dublin and half of Leinster - James fled to Dublin and within three weeks of the battle, was ensconced in France.
Today, you can see King William's Glen, on the eastern edge of the Townley estate, about 6 km (4 miles) west of Drogheda. The glen, extending for about 1.6 km (1 mile), was used by part of the Williamite army to conceal its approach to the Boyne. From the viewing platform, you can see the layout of the battlefield. There's a small information centre in a portakabin, which has plenty of detail available on the site. Plans exist to build a full-scale heritage centre here.
Battle of the Boyne Information Centre, near Drogheda, Co. Louth; tel (041) 9841644 (open daily during the summer).
The battle itself is commemorated every year in the North, at the so-called Sham Fight in the grounds of Scarva House, Scarva, Co. Down, on 13 July annually. In the meantime, back in the Boyneside town of Drogheda, the new Drogheda Heritage Centre has a fine audio-visual presentation on 800 years of the town's history. This includes Cromwell's bloody siege of Drogheda in 1649, when his forces killed 2,000 of the town's inhabitants and sent most of the survivors to Barbados. This audio-visual display has a substantial element on the Battle of the Boyne.
Drogheda Heritage Centre, Drogheda, Co. Louth; tel (041) 9836643 or 087 2305698; email email@example.com (open Tues-Sat 10am-5pm, Sun 2pm-6pm, all year).
Other example tours:
Architecture, Old and New Dublin
For further details on other trails: Travellers' Trails: Ireland by Hugh Oram, from Appletree Press.