County Laois (pronounced "leesh") (Contae Laoise) is in the East Coast and Midlands region of Ireland. Historically it was on the western fringe of Leinster, but modern transport puts it within commuting distance of Dublin, only an hour away.
Ireland began on two continents separated by the Iapetus Ocean. Over 400 million years ago the ocean closed up, and a line of mountains formed where the continents fused. These towered over 3000 m high, but were of sandstone that quickly eroded, leaving the 500 m peaks of the Slieve Bloom Mountains. They formed a natural boundary between the ancient kingdoms of Leinster to the east and Munster to the west, and a semi-independent "buffer state" of Osraige or Ossory emerged along this upland strip. Its people were the tribe of Ui Laoighis, pronounced "Leesh", who were traditionally composed of seven "septs" or clans - the leading clan being the O'Mordha, aka O'More or Moore.
The O'Mores sided with Leinster but in the 12th century the Normans arrived, grabbed the best land, and re-organised the territory into shires or counties. But their control this far west was tenuous, they were distracted by plagues and other wars, and Laois was among the areas that repulsed them in the 13th / 14th centuries and restored Gaelic rule. The Tudors resumed the task of subduing Ireland, and in 1556 under Mary I they created Queen's County, with its county town at Maryborough. They ejected the O'Mores and colonised the area with "Plantations" of loyal English settlers, but this was a stuttering process, with Irish counter-attacks and limited numbers of incomers. There were also French Huguenot settlers in the 1690s, and Quakers from the 18th century, who developed industries such as textiles. Mountmellick for instance, now a quiet little place, once rang with the clamour of forge-mallets and looms. But it wasn't on a large enough scale to change the ethnic balance (as it did in the Ulster textile towns) or to protect against the famine years, when the population slumped.
The modern county is "double land-locked" - surrounded by counties that are themselves land-locked, if you discount tidal rivers. At independence in 1921, "Maryborough" became Portlaoise and the county unofficially became Laois, though this wasn't enshrined in law. So legally it's still "Queen's County" just as neighbouring Offaly remains "King's County" for Mary's husband, Philip II of Spain. The mountains and bogs of Laois constrain the transport routes: the railway arrived in 1847, and Mountrath became a bottleneck on the Dublin - Limerick road until bypassed in 2010. Portlaoise developed industry, but what chiefly reversed the population decline was the ease of commuting to Dublin, only an hour away by road or rail. In 2016 the county population was 84,697, a 26% increase on 2006.
The county tourist agency promotes Laois under the slogan "You're welcome". The national agency Discover Ireland covers it as part of "Ireland's Ancient East", which roughly means Leinster.
Trains from Dublin Heuston run hourly via Sallins (for Naas), Newbridge, Kildare and Monasterevin to Portarlington and Portlaoise. They continue south to Ballybrophy (for the branch to Roscrea and Nenagh), Thurles, Limerick or Cork, or west to Tullamore, Clara and Athlone, where they branch either for Galway or for Roscommon and County Mayo. See Irish Rail for timetables, fares and online tickets.
Dublin Coach N7 runs every 2 hours from Dublin Airport via Kildare to Portlaoise. From Dublin city take their M7 bus towards Limerick, and change at Kildare for the N7 to Portlaoise or the 816 to Portarlington.
Bus Éireann 73 trundles across the midlands twice a day from Waterford via Thomastown, Kilkenny, Carlow and Stradbally to Portlaoise and Mountmellick. It continues to Tullamore, Clara, Moate and Athlone.
By road from Dublin follow N7 / M7 and reckon an hour.
Train is a good option between Portlaoise and Portarlington. Bus routes fan out from Portlaoise to the county's other towns but service is sparse, often only twice a day, and attractions such as Rock of Dunamase or the trailheads for Slieve Bloom have no public transport. So you need wheels. The distances are not great so a bike would do, but a car gets you out of the rain.