Athlone, Tullamore and Mullingar were also among those surveyed.
Portlaoise is the cleanest town in the country.
The first post-lockdown survey by Irish Business Against Litter finds 68 per cent of towns registered improvements last year.
Athlone and Tullamore have retained their status as clean to European norms - ranking 12th and 15th respectively, while Mullingar has been deemed moderately littered.
That is mostly due to the area surrounding the canal, according to those behind the survey.
IBAL spokesperson, Conor Horgan says Portlaoise has done brilliantly to come out on top:
The An Taisce report for Portlaoise stated:
Portlaoise has built on years of concerted effort and steady improvement to top the IBAL table for the first time. With so many top-ranking sites, there are a few which deserve a special mention. Fitzmaurice Place - formerly an amphitheatre - has now been transformed into a beautiful green space with lovely seating, grass area and planting.
The Main Street and Church Street were both excellent in terms of streetscape and litter. Clearly a careful eye is kept on the Derelict Sites on Pepper Lane – while they presented poorly, there was no litter directly associated with them. The moderately littered area to the rear of the library was the only blemish in the town.
The An Taisce report for Tullamore stated:
Another excellent showing by Tullamore in what has been a fine year for Midlands towns. All three approach roads surveyed got the top litter grand, creating a positive first impression of the town. This high standard was maintained for many of the other sites surveyed, a couple of which deserve further mention e.g. The Square is a beautifully laid out town centre environment which was excellent with regard to litter.
Columcille Street was very much deserving of the top litter grade and clearly a careful eye is kept on the boarded up white premises as there was no litter directly associated with it. By far the most heavily littered site in Tullamore was the Bring Centre, Council Car Park – it wasn’t just casually littered but subject to significant dumping of black sacks to the front of the units and miscellaneous items to the rear.
The An Taisce report for Athlone stated:
A very good result for Athlone with over the half of the sites surveyed getting the top litter grade and just one seriously littered site. The town centre sites were the ones which tended to get the top litter grade e.g., Athlone Castle, Car Park at Golden Island Shopping Centre, Sean Costello Street / Dublin Gate Street / Church Street and the Riverwalk from Athlone Castle to the White Bridge.
In many instances the overall environment was enhanced by seating, planting and good visitor information notices. By far the most heavily littered site surveyed was Athlone Municipal Recycle Facility – it wasn’t just casually littered but there were heavy accumulations of a wide variety of litter at the base of the shrubbery around the perimeter.
The An Taisce report for Mullingar stated:
A significant improvement for Mullingar after a disappointing result in late 2020. All three of the approach roads which were surveyed got the top litter grade. Other top-ranking sites included Oliver Plunkett Street (the pedestrianised zone was particularly freshly presented and maintained) and the Town Park – a lovely park environment with all elements within, in good condition.
By far the most heavily littered site surveyed was the Canal – it wasn’t just casually littered but subject to dumping of larger items e.g., shopping trolley and other miscellaneous items. The Bring Centre at Council Building Car Park was a poor site due to the state of the area to the rear of the units.