Portlaoise (older spelling Portlaoighise; former name Maryborough), is the county town of County Laois (formerly Queen's County) in the midlands of the Republic of Ireland. The name is Irish for "Fort of Laois", and properly pronounced ; however, a partially anglicised pronunciation as "Port Laois" is common, although the inland town is not a port. The population in 2002 was 12,127.

The town was first established by Queen Mary in 1556 as "the Fort of Maryborough". Signs of the old garrison remain all over the town, and the old jail has been transformed into an arts centre. Nearby is the Rock of Dunamase, an ancient Celtic fortification, allegedly recorded by Ptolemy in the 1st century. Also nearby are Emo Court, an 18th-century country house designed by James Gandon; Ballyfin House, now a private school; and Mountmellick, the site of a notable Georgian square.

The town is a major commercial, retail, and arts centre for the Irish midlands. It is home to the maximum-security Portlaoise Jail , which houses the majority of Northern Irish terrorists sentenced in the Republic, and to the Midlands Prison. Both establishments are major employers in the town.

Portlaoise stands at a major crossroads in the Irish roads network although construction in recent years of the M7 motorway, which bypasses the town, has reduced traffic congestion in the town centre. The town has a railway station served by intercity trains between Dublin and Cork and by Dublin commuter services.

See also

• List of towns in the Republic of Ireland