Irish running is more concentrated than the map suggests. Four counties — Dublin, Galway, Kerry and Cork — carry most of the race calendar and nearly half the parkruns, and the rest of the country runs a quieter club scene that almost never appears in a national listing. This is all 26 counties of the Republic, what the ground is like, and what actually happens there.
parkrun figures below are 5K events only, from parkrun's own feed. Junior events are additional.
Leinster
Dublin — 26 parkruns
The centre of Irish running by a distance. Phoenix Park at 1,750 acres, a coastal path from Sandymount to Howth Head, and the Wicklow foothills reachable by tram to Marlay Park. The Dublin Marathon on the last Monday of October is the biggest event in the country at around 20,000 runners, and the Dublin Race Series builds towards it across the summer. The Raheny 5 in January draws 3,500 to a five-mile road race that starts at three in the afternoon.
Wicklow — 3 parkruns
The mountain county, and the home of Irish trail and ultra running. The Wicklow Way runs 127km down its spine from Marlay Park to Clonegal. Blanket bog on the tops, forest fire road lower down, and moderate climbs that add up. Carries the Art O'Neill Challenge in January, the Maurice Mullins in March, Ultra Trail na mBan in April and the full Wicklow Way Race in July — the densest ultra calendar in Ireland.
Meath — 5 parkruns
Boyne Valley farmland, gently rolling and fast. Two of the fixtures that open the Irish road season are here: the Trim 10 Mile at the end of January, starting on the Athboy Road beneath the largest Anglo-Norman castle in Ireland, and the Bohermeen Half Marathon in early March.
Kildare — 2 parkruns
Flat, horse country, and the home of Donadea Forest Park — a lapped forest circuit that hosts the Donadea 50K in February, the fastest and best-known entry-level ultra in Ireland.
Louth — 1 parkrun
The smallest county in Ireland, on the Boyne coast north of Drogheda. The Termonfeckin Half Marathon in July, with a four-mile option, is the fixture.
Wexford — 3 parkruns
The south-eastern corner and the sunniest part of the country, which by Irish standards is a low bar cleared. Long beaches, flat coastal road, and the Wexford Half Marathon in April.
Carlow — 1 parkrun
The second-smallest county, on the Barrow. Quiet running, the southern terminus of the Wicklow Way at Clonegal, and a family 5K at Rathwood put on by Tullow Marathon Runners.
Kilkenny — 1 parkrun
Medieval city on the Nore with one of the better-preserved historic centres in Ireland. The Kilkenny Half Marathon in September runs the city and the country around it.
Laois — 1 parkrun
Midlands, flat, with the Slieve Bloom mountains on the Offaly border — the main trail-running ground in the middle of the country. The Portlaoise Half Marathon is the county fixture.
Offaly — 2 parkruns
Bog and midlands farmland, with the Slieve Blooms shared with Laois. The Frank Kilrane 10 Mile at Edenderry in July is the third of four races in the Offaly Endurance Series — a county series structure that is how a lot of midlands road racing works.
Westmeath — 2 parkruns
The middle of Ireland, where the Shannon widens into Lough Ree. Athlone is the centre of it, and the Athlone AC Half Marathon in September is flat midlands road running.
Longford — 1 parkrun
Quiet midlands county. The Royal Canal Run Longford Half Marathon in April runs on canal towpath — flat, traffic-free and consistent for the whole distance.
Munster
Cork — 11 parkruns
The largest county in Ireland and the second-biggest running scene. Cork City Marathon in June is now a ballot across all three of its distances. Charleville in the north of the county bills itself as the flattest, straightest half marathon in Ireland and is where Irish runners go for a personal best. Clonakilty runs a late-November marathon on the West Cork waterfront, and the Beara peninsula in the far south-west carries the 130km Beara Way Ultra.
Kerry — 5 parkruns
The highest ground in Ireland and the best running in it. The Dingle Marathon in September on the Slea Head road at the far south-western tip; the Kerry Way Ultra's 200km circuit of the Ring of Kerry from Killarney on the first weekend of September; Hardman Killarney, billed as the country's only full-distance triathlon; and the Lost Sheep at Kenmare, whose bike leg crosses three mountain passes. Tralee runs a spring half on the flat land at the head of the bay.
Clare — 4 parkruns
The Burren, which looks like nowhere else in Ireland — bare limestone pavement cut with grikes, crossed by the Clare Burren Marathon Challenge in May on green roads and boreens. On the coast, Kilkee hosts the Hell of the West, the oldest triathlon of its kind in Ireland and one named for the West Clare wind rather than its terrain.
Limerick — 3 parkruns
City on the Shannon. The Limerick Marathon on the May bank holiday weekend is the first of the big Irish city marathons in the year, with a half and a team relay alongside it.
Tipperary — 5 parkruns
Inland county with the Galtees and the Comeraghs on its southern edge. Clonmel in the Suir valley is the centre of the running — a half marathon, and a well-established summer evening series of short races in the town.
Waterford — 2 parkruns
Home of the John Treacy Dungarvan 10 in early February, named for the Waterford man who took Olympic marathon silver in 1984 — now the spring ten-miler the Irish club calendar is built around, and effectively the successor to the departed Ballycotton 10. Waterford city runs its own marathon in June.
Connacht
Galway — 9 parkruns
The most race-dense county outside Dublin, and the one people travel furthest for. Connemara carries the Connemarathon at the end of April — ultra, marathon and half all finishing at Maam Cross — and the crewed Connemara 100 in August. Galway city runs the Run Galway Bay marathon, half and 10K from the Claddagh in October, and the Streets of Galway 8K on an August Saturday evening during Race Week. Lough Cutra Castle near Gort hosts a triathlon festival on a private lake.
Mayo — 7 parkruns
Achill Island is the largest island in Ireland and one of the most exposed places to run anywhere in these islands; its half marathon on the Atlantic Drive sells out every year. Westport, under Croagh Patrick on Clew Bay, is the best small-town base in the west and runs its own half in April.
Sligo — 2 parkruns
Yeats country, with Benbulben and the Dartry mountains giving the north-west its most recognisable skyline. The Sligo Trail Run in summer is the fixture.
Roscommon — 3 parkruns
Quiet west midlands. Roscommon Harriers put on a ten-mile road race in June at €30 — the kind of club fixture that makes up the bulk of the Irish calendar and almost never appears in a national listing.
Leitrim — 2 parkruns
The least populated county in Ireland, on the upper Shannon at Carrick-on-Shannon, and correspondingly quiet roads. That is either a drawback or the entire point, depending on what you want from a race.
The Ulster counties in the Republic
Three of Ulster's nine counties are in the Republic. The other six are Northern Ireland and are covered on this site under the UK, though the running scene crosses the border constantly in both directions.
Donegal — 6 parkruns
The least-visited running country in Ireland and among the best — the far north-west, exposed Atlantic coast, and Errigal above it. The Donegal Quadrathon in August carries a marathon and a half as part of a four-day multi-sport event.
Cavan — 4 parkruns
Drumlin country: small steep hills in constant succession, which makes for a deceptively hard road course. The Cavan Half Marathon is the fixture, and the hills never quite stop.
Monaghan — 2 parkruns
The same drumlin landscape as Cavan, on the border. Short, steep, relentless hills rather than long climbs, and a half marathon from the county town.
The pattern worth noticing
Ireland's running divides cleanly into two calendars. There is the destination calendar — Connemara, Dingle, the Burren, Kerry, Achill — which is what visitors come for and which is concentrated on the Atlantic coast. And there is the club calendar, which is everywhere else: ten-milers and half marathons at €30 to €50, organised by clubs, published a few weeks ahead, and largely invisible outside the county.
The second one is the larger of the two and the harder to find. If you are living in Ireland rather than visiting, it is the one that matters, and the way in is the local club rather than any national listing.