Just off the M6, Ballinasloe (Béal Átha na Sluaighe) is famed for its historic horse fair, which dates right back to the high kings of Tara. The fair has an old-time carnival atmosphere, created by the 80,000-plus horse traders and merrymakers who roll into town. They include Ireland's Traveller community, who camp nearby in traditional barrel-topped wagons.
Around 6km southwest of town on the R446, Aughrim was the site of the bloodiest battle ever fought on Irish soil, which ended in a crucial victory in 1691 by William of Orange over the Catholic forces of James II. The Battle of Aughrim Interpretive Centre helps place it within the context of the War of the Two Kings. Battle sites pepper the surrounding countryside, but thickets of signs often leave visitors going in circles when the centre is closed (it has essential directions).
Heading 21km southeast of Ballinasloe brings you to 12th-century Clonfert Cathedral. It's on the site of a monastery said to have been founded in AD 563 by St Brendan 'the Navigator', who is believed to be buried here. Although the jury is out on whether St Brendan reached America's shores in a tiny currach.
The marvellous six-arch Romanesque doorway, adorned with surreal human heads, is reason enough to visit. The cathedral is off the R356.