Find the Cross of the Scriptures and read the carved panels on it

Walk between the nine ruined churches and the two round towers

Look at the collection of over 700 early Christian graveslabs

Stand at the river and work out why the Esker Riada made this the crossroads of the country

Saint Ciarán, a Roscommon man from Rathcroghan, founded Clonmacnoise on the Shannon in 544 — and he chose the spot for a reason. This is where the Slighe Mhór, the great east–west land route, met the river after crossing the central bogs along the Esker Riada. Whoever held it controlled the crossroads of Ireland, which is why kings were buried here and why it was raided again and again. Nine ruined churches, two round towers, a castle and one of the greatest collections of carved crosses and cross-slabs in the country still stand on the riverbank.

Clonmacnoise: Where the Road Met the River

Clonmacnoise and the Shannon

Dublin

Ten nights in a loop from Dublin to the west and back: Clonmacnoise on the Shannon, three nights in Connemara for Roundstone, the Sky Road and Killary, then Croagh Patrick and Athlone.

Connemara and the West from Dublin

Tour Athlone Castle, whose polygonal tower of 1210 is still the keep

Take a boat out onto Lough Ree from Athlone harbour at the lake's southern end

Walk Athlone's Left Bank, the old quarter between the castle and the river

Look up the lake to where Longford, Westmeath and Roscommon share its shores

Athlone grew up where the Shannon could be crossed, and that is why there is a castle here. The stone castle was built in 1210 for King John by his justiciar, John de Gray, bishop of Norwich, on a motte by the river, to hold the crossing and give the Normans a bridgehead into Connacht; it stands on or near the site of a wooden castle raised in 1129 by Tairrdelbach Ua Conchobair, and its polygonal tower of 1210, greatly altered, is still the keep. The town sits at the southern end of Lough Ree, the second-largest lake on the Shannon after Lough Derg, which forms the border between Longford and Westmeath on the east and Roscommon on the west. The old quarter, the Left Bank, is squeezed between the castle and the river.

Athlone and the Shannon's Lough Ree Shore

Have a drink in Sean's Bar, certified by Guinness World Records in 2004 as the oldest pub in Ireland

Weigh up the claim: AD 900 by tradition, about 1725 by the official records

Walk out to the Shannon crossing in front of the pub, the reason Athlone is here

Walk up to Athlone Castle, built in 1210 to hold the same crossing

Sean's Bar on Main Street in Athlone, by the Shannon crossing, claims to have been founded in AD 900 and to be the oldest bar in Ireland, and in 2004 Guinness World Records issued it a certificate as the 'oldest pub in Ireland'. The official records disagree: the Record of Monuments and Places and the National Inventory of Architectural Heritage date the building to the 17th or 18th century — about 1725, possibly with fabric from earlier buildings — and a rental survey of 1738 calls it the Three Blackamoor Heads. When it was renovated in the 1970s, part of a back wall turned out to be wattle and wicker, and tavern tokens of uncertain age were found; they are now in the National Museum of Ireland.

Sean's Bar: The Claim to Be Ireland's Oldest Pub

Walk the harbour and the lock where the canal drops into the Shannon

Find the ruins of the canal hotel that housed passengers overnight

Walk the Grand Canal towpath east from the harbour across the bog

Have a pint in one of the two pubs and watch the boats work the lock

Shannon Harbour is where the Grand Canal finally reaches the Shannon after crossing the bogs from Dublin, and for a century it was one of the busiest inland ports in Ireland — passengers and freight transferring between canal boats and river steamers, with a hotel to hold them overnight. The traffic went and the village stayed: a handful of houses, a lock, docking for boats, and two pubs. It is one of the quietest places on the whole waterway, and the junction survives largely as it was build canal junction in the country.

Shannon Harbour: Where the Grand Canal Meets the River

Walk out to Cromwell's Castle, Cromwellian in origin from 1653 and rebuilt as a gun position in the Napoleonic wars, still standing over the Shannon crossing

Find the Salt Battery — Fort Eliza — with its emplacements for four cannons, and the Martello tower

Walk the harbour and the marina on the Shannon

Find Charlotte's Way, the house once called Hill House, where Charlotte Brontë's widower lived out his life, and the house Trollope lodged in

Banagher sits on one of the very few crossings of the mid-Shannon, and it is fortified out of all proportion to its size. Cromwell's Castle, built in 1653, still stands controlling the river; so do the Salt Battery — Fort Eliza — with emplacements for four cannons, Fort Falkland, and a 19th-century Martello tower, all of them put there to hold one bridge. Anthony Trollope lived here in the 1840s, and Arthur Bell Nicholls came back to Banagher after the death of his wife Charlotte Brontë and lived at Hill House until 1906.

Banagher: The Shannon Crossing and Cromwell's Bridgehead

Walk the sculpture park and find the first pieces, made on the bog in 2002

Cycle or walk the trails across the cutaway bog

Find out what the Mesolithic camp found at Boora says about the first people here

Walk down to the angling lakes and the nature reserve

Boora Bog was cut away for peat by Bord na Móna, and the lake that gave it its name was drained. What was left has been given back: a nature reserve kept by the Irish Wildlife Trust, angling lakes, and Sculpture in the Parklands, a 50-acre land and environmental sculpture park that began in 2002, when seven Irish and international artists spent three weeks making the first pieces out on the bog. Excavations here also found a temporary camp from the Mesolithic.

Lough Boora: Sculpture on a Cutaway Bog

Walk the boardwalk trail into Clara Bog, one of the best-preserved raised bogs left in Western Europe, its pools and hummocks fed by rain alone

Tour the Tullamore D.E.W. visitor centre in the old bonded warehouse and find out who Daniel Edmund Williams was

Find where the road split the bog into two domes, western and eastern

Find the flush pools where alkaline groundwater supports plant life found nowhere else on the bog

Clara Bog is one of the best-preserved raised bogs left in western Europe — a dome of peat fed by nothing but rain, with its own pattern of pools and hummocks, crossed by a boardwalk so you can see it without damaging it. Around the edges, flush pools fed by alkaline groundwater support plants found nowhere else on the bog. The reserve covers some 460 hectares, and a road cut across the bog long ago left it with two domes, a western and an eastern. Ten minutes away in Tullamore, the whiskey goes back to the distillery founded in 1829 and carries the initials of Daniel Edmund Williams, its general manager and later owner; the new distillery opened in 2014.

Clara Bog and Tullamore D.E.W.

Get out on a clear moonless night away from the village lights and let your eyes adapt for twenty minutes

Trace the Milky Way from horizon to horizon

Find one of the reserve's designated viewing points on the Skellig Ring

Learn why Gold Tier is the highest dark-sky grade there is, and what it takes to keep it

The Iveragh Peninsula between Kells and Caherdaniel holds Ireland's first International Dark Sky Reserve, and on 27 January 2014 the International Dark-Sky Association gave it Gold Tier — the first Gold Tier Reserve in the northern hemisphere and one of only four in the world. There is no town light bleeding in from anywhere, the Atlantic is on three sides, and on a clear moonless night the Milky Way is not a faint smudge but a structure you can trace from one horizon to the other.

The Kerry Dark Sky Reserve: Gold Tier on the Iveragh

Drive the hairpins of the Glengesh Pass south out of Ardara

Stop at the top of the pass and look back down the glen

Find a working handweaver in Ardara and watch Donegal tweed being made

Walk Maghera Strand and look into the sea caves under Slievetooey at low tide

Stop at the Assaranca waterfall on the road out to Maghera

Ardara is the weaving town of south-west Donegal, where Donegal tweed is still made by hand, and the road south out of it climbs the Glengesh Pass in a set of hairpins onto empty moorland before dropping away towards Glencolmcille. It is one of the great short drives in Ireland and it takes about ten minutes, which is the joke of it. West of the town, below Slievetooey, Maghera Strand hides more than twenty sea caves that you can only reach when the tide is out, and on the road out to it is the Assaranca waterfall.