Other local historical features include Dun Ailinne, New Abbey and Castlemartin, for many years the home of media magnate Tony O'Reilly and his wife, horse-breeding shipping heiress Chryss Goulandris, and now owned by US billionaire John Malone.

First built in the 1310s, the six-arch bridge over the Liffey was last reconstructed c. 1850, and renovated and widened in the early 1970s; the upstream face is modern while if viewed from downstream, the historic style is visible.

At the western edge of the town is the Pinkeen Stream, a minor tributary of the Liffey, which forms one boundary of Castlemartin Estate.

Schools and churches are concentrated at the southwestern edge, businesses spread along the main street and near the old market square, and the town hall and theatre (former cinema) and heritage centre, and a bank, lie just to the northeast of the bridge.

The town was in the vicinity of the Battle of Kilcullen in the 1798 Rebellion, and Castlemartin was the base of operations for the British Army in Kildare, under Dundas.

In 1837, the official town area had a population of 699, one principal street of 112 buildings, chiefly on the western bank of the Liffey, a market on Saturdays and fairs on 2 February 25 March, 22, 8 June and 29 September 2 October and 8 December.

Old Kilcullen may have related to the reputed site of a palace or ceremonial place of the Kings of Leinster at Dun Ailinne, on an adjacent hill.

Two of these, and outlying buildings, opening off the northern part of Main Street, were planned to be redeveloped as apartments, restaurants and shops, with permission granted on 15 February 2008.

Kilcullen has an early church of its own, around 1 km (0.62 mi) outside the town, the New Abbey, commenced in 1486 by Rowland FitzEustace, 1st Baron Portlester and Lord Chancellor of Ireland.

Features include a walled garden and formal walk, the library, French and Italian furniture and 18th-century Chinese wallpaper.

After some lobbying, a number of local laws were changed, and Kildare was chosen as the venue – partly because the straightness of the roads was deemed a safety benefit.

Today the town hall has historical displays, formed and maintained in cooperation with the active Kilcullen Heritage Group, and with the Kildare County Library Service.

A major feature of the town is the narrow but extensive Valley Community Park, which runs along the River Liffey, and related walks, one of which goes all the way to New Abbey.

Located in the former boys' schoolhouse, built in 1925 and operating until 1980, it holds adult, reference and junior sections, some local history information, and a public access internet PC.

One of their major fund-raising events is the Duck Race in the Liffey, which since 2010 formed part of a larger community-led River Festival.

There is an active local Scout group, and a well-established credit union, with a large office near the town bridge, as well as the Kilcullen Flower and Garden Club.

There is a long-running local magazine, The Bridge, published monthly, and the area is also covered with a section in the Kildare Nationalist newspaper.

The owner of the facility made available funding over many years, notably from 2000 to 2006, from a levy on dumping there, to support the work of local groups such as the Tidy Towns Committee.

There is also a successful badminton club in the area which has both junior and senior members competing in inter-county tournaments and competitions such as the Westside and the county championships.

There is a 4.1 km (3 mi) Sli na Slainte healthy walking route around the area, passing the graveyard, St. Bridget's Well, the bridge and Bishop Rogan's Park.

The area historically enjoyed a number of swimming locales in the Liffey (one at Carnalway, one in The Valley and one opposite Castlemartin House) and walking routes along its banks (at least one of which is a right-of-way), but access has become more difficult in recent years, and a bitter dispute over riverbank access took place at Carnalway from 2005 to 2007, featuring unauthorised construction of fencing and obstruction of rights of way.

The Liffey at Kilcullen is known for trout angling and the North Kildare TSAA manages fishing rights from Harristown through to the town centre.