Birr (/ˈbɜːr/; Irish: Biorra, meaning "plain of water") is a town in County Offaly, Ireland.

The town is known for Birr Castle and Gardens: the home of the Parsons family and the site of the Leviathan of Parsonstown, which was the largest telescope in the world for over 70 years.

Birr railway station, the terminus of a branch from the Limerick–Ballybrophy line at Roscrea, opened on 8 March 1858 and closed on 1 January 1963.

The Tuatha was subject to the overkingdom (Irish: Rí ruirech) of Munster and formed a border with the Kingdom of Meath to the east.

This is all the more puzzling when the Birr Georgian Society were refused the opportunity to restore the building into a Museum following minor interior damage during preliminary works some years ago.

[citation needed] Birr Barracks became the depot of the Prince of Wales's Leinster Regiment (Royal Canadians) from 1881.

The barracks at Birr was burned down in 1922 during the Irish Civil War and the outer perimeter wall is all that remains.

[13] Outside the old Barracks Wall, there is a monument erected in memory of the soldiers of the Leinster Regiment who were killed during their service.

The Oxmantown Mall was laid out in the early 19th century and was designed as a promenade leading from Birr Castle gates to the Church of Ireland.

Birr Town Council met here in a building known as John's Hall built in the style of a Greek Temple.

Mentioned by Geraldus Cambrensis, who referred to it as Umbilicus Hiberniae, the indentations on the stone are as old as megalithic sites, such as Newgrange.

In the 16th century, the O'Carrolls of Éile had one of their castles here and this was granted to the English-born politician and judge Sir Lawrence Parsons in the course of the Stuart plantation, c. 1620.

The castle was twice besieged in the 17th century and one of the towers still shows the scars of the artillery of Patrick Sarsfield, 1st Earl of Lucan, who tried unsuccessfully to take it.

As a family home, most of the castle is only open to the public on special occasions, though five reception rooms can be visited, by guided tour only, through the demesne's visitor centre.

The castle's demesne, however, is open to tourists every day of the year, and the gardens comprise a landscaped park with waterfalls, rivers and a lake, as well as the large reflecting telescope, the Leviathan of Parsonstown, and the modern radio-telescope, I-LOFAR.

On 31 August 1869, the first road fatality recorded in history occurred in Birr, when local-born scientist Mary Ward, a cousin of The 3rd Earl of Rosse, fell from a steam-powered car on a bend.

A descendant of the O'Carrolls, Charles Carroll was the first and only Catholic to sign the United States Declaration of Independence and, also, the only signatory to give his address.

[citation needed] The first ever All-Ireland hurling final was played in Hoare's field (currently the location of a Tesco store) in Birr on Easter Sunday, 1 April 1888, between Tipperary and Galway.

The course was founded originally at Barrone Court, moving to its present location at the Glenns, north of Birr, in 1909.

[23] The annual Birr Vintage Week and Arts Festival takes place in the town in August.

[25] The building dates from January 1889 and is a Victorian period style structure within the surrounds of the tree lined Oxmantown Mall.

[27] Birr, classified as an oceanic climate by Köppen, has cool winters, mild summers and adequate rainfall year-round.