In 2022, it had a population of 26,180, making it the largest town in County Kildare (ahead of Newbridge) and the fourteenth-largest urban centre in Ireland.

Irish mythology suggests that the name arose as the burial site of Nás (a wife of Lugh of the Tuatha De Danann).

“Nás of the Leinstermen, bright with splendid bounty, ‘tis there the lady was buried; from her it is called with clear certitude: the lore of the ancient hides not this.”In the Middle Ages, Naas became a walled market town and was occasionally raided by the O'Byrne and O'Toole clans from the nearby area which became County Wicklow.

[14] In 1409, King Henry IV of England granted Naas its first charter as a corporation, consisting of Portreeves, Burgesses and Commonality.

On 3 March 1577, Lord Rory O'More burnt Naas, to avenge his relatives who had been killed by English authorities.

[19][20] Lord Deputy Sir Henry Sidney wrote later the same month:Rory Oge O'More and Cormock M'Cormock O'Conor have burnt the Naas.

They ranne thorough the towne lyke hagges and furies of hell, with flakes of fier fastned on poles ends.

[21]In 1595 Robert Ashe, Sovereign of Naas, says on oath that the charter granted the town by Elizabeth I had been accidentally burned.

[15] In 1628 a further charter of King James grants the corporation the right to pass byelaws provided that they are consistent with the laws of the kingdom.

[24] Local industrial enterprises include Kerry Group's Global Technology and Innovation Centre,[25] and International Fund Services (a State Street company).

A shopping centre on Monread Road was completed in 2010 with Ireland's largest Tesco Superstore as the anchor tenant.

Other retail parks serve the town on both ends – northern and southern – with outlets such as Harvey Norman, PC World, B&Q, Smyths Toys, and Halfords.

Naas railway station, which opened on 22 June 1855, closed for passenger traffic on 27 January 1947 to be re-purposed for goods trains.

[citation needed] The main bus transportation companies serving the area are Go-Ahead Ireland, JJ Kavanagh and Sons and Dublin Coach.

[50] The Moat Theatre is a 200-seat performance and visual arts centre in Naas, which hosts local and national stage productions, live music and other events.