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ST THOMAS JUNIOR NATIONAL SCHOOL

Roll number: 19542R Newcastle Road, Lucan, Co. Dublin

School details

Address: Newcastle Road, Lucan, Co. Dublin (K78PF57)
Email: [email protected]
Phone: 016282691
Principal: Teresa Moynihan
Ethos: Catholic
DEIS: N
Irish classification: No subjects through Irish
Gaeltacht: N
Island: N
Local authority: South Dublin County Council
School patron: Archbishop of Dublin
School type: Ordinary
School level: Junior
Planning area: Lucan

Class size history

Mainstream class group data is shown separately from standard/year-group enrolment data. The source does not identify which standard/year group each class group belongs to.

Average class size

25.77

2025/26

Mainstream classes

2025/26

Largest class group

2025/26

Classes with 30+ pupils

2025/26

Class group metrics trend

Class group metrics by year

Year	Mainstream class pupils	Mainstream classes	Average class size	Largest class	Classes 30+
2006/07	460	16	28.75	30	1
2007/08	457	16	28.56	30	3
2008/09	476	17	28.00	29	0
2009/10	506	18	28.11	29	0
2010/11	505	18	28.06	30	1
2011/12	512	18	28.44	30	3
2012/13	514	18	28.56	30	2
2013/14	511	18	28.39	29	0
2014/15	542	19	28.53	30	2
2015/16	556	20	27.80	29	0
2016/17	572	20	28.60	30	3
2017/18	560	20	28.00	30	5
2019/20	569	20	28.45	30	2
2020/21	568	20	28.40	30	5
2021/22	548	20	27.40	30	3
2022/23	543	20	27.15	30	2
2023/24	523	20	26.15	28	0
2024/25	562	21	26.76	30	4
2025/26	567	22	25.77	30	1

Data highlights

Key numbers to spot outliers or notable changes.

Biggest gain in a single year: 1979/80: 314 in 1978/79 → 462, +148 pupils.
Biggest loss in a single year: 1993/94: 685 in 1983/84 → 353, -332 pupils.
Largest single-class increase: Junior Infants in 2024/25 (123 → 148, +25).
Largest single-class decrease: 1st Class in 2025/26 (145 → 132, -13).
Largest cohort-step gain: SI → 1st in 2024/25 (126 → 145, +19).
Largest cohort-step loss: 2nd → 3rd in 2025/26 (148 → 0, -148).
Overall: 99 (1976/77) → 573 (2025/26), 474.

Summary statistics (class-level data)

Min / max / mean enrolment per class across the available final by-standard years.

Class	Min	Max	Mean	Years
Junior Infants	123	150	133.7	6
Senior Infants	126	149	136.8	6
1st Class	132	145	139.2	6
2nd Class	139	148	144.2	6
3rd Class	0	0	0.0	1
4th Class	0	0	0.0	1
5th Class	0	0	0.0	1
6th Class	0	0	0.0	1
Total	99	685	468.8	41

Total enrolment over time

Total and gender trends use historical records where available. Class-level data starts in 2020/21.

Enrolment by gender over time

Enrolment by class over time

Cohort progression

Base cohort:

Track how each cohort (pupils who were in the same class in the same year) progresses through the school. Each step shows the count; the number between steps is the net change (pupils gained minus pupils lost).

Cohort 2020/21

JI 2020/21 133

SI 2021/22 138

1st 2022/23 138

2nd 2023/24 139

-139

3rd 2024/25 0

4th 2025/26 0

Cohort 2021/22

JI 2021/22 123

+11

SI 2022/23 134

1st 2023/24 135

+13

2nd 2024/25 148

-148

3rd 2025/26 0

Cohort 2022/23

JI 2022/23 125

SI 2023/24 126

+19

1st 2024/25 145

-3

2nd 2025/26 142

Cohort 2023/24

JI 2023/24 123

SI 2024/25 127

1st 2025/26 132

Cohort 2024/25

JI 2024/25 148

SI 2025/26 149

Cohort 2025/26

JI 2025/26 150

Raw data by year

Year	Female	Male	JI	SI	1st	2nd	3rd	4th	5th	6th	Total
1976/77	38	61	–	–	–	–	–	–	–	–	99
1977/78	75	121	–	–	–	–	–	–	–	–	196
1978/79	–	–	–	–	–	–	–	–	–	–	314
1979/80	205	257	–	–	–	–	–	–	–	–	462
1980/81	247	295	–	–	–	–	–	–	–	–	542
1981/82	267	317	–	–	–	–	–	–	–	–	584
1982/83	282	371	–	–	–	–	–	–	–	–	653
1983/84	287	398	–	–	–	–	–	–	–	–	685
1993/94	165	188	–	–	–	–	–	–	–	–	353
1994/95	160	179	–	–	–	–	–	–	–	–	339
1995/96	173	188	–	–	–	–	–	–	–	–	361
1996/97	158	181	–	–	–	–	–	–	–	–	339
1997/98	149	174	–	–	–	–	–	–	–	–	323
1998/99	155	195	–	–	–	–	–	–	–	–	350
1999/00	158	202	–	–	–	–	–	–	–	–	360
2000/01	172	218	–	–	–	–	–	–	–	–	390
2001/02	187	233	–	–	–	–	–	–	–	–	420
2002/03	197	244	–	–	–	–	–	–	–	–	441
2003/04	229	231	–	–	–	–	–	–	–	–	460
2004/05	220	246	–	–	–	–	–	–	–	–	466
2005/06	226	237	–	–	–	–	–	–	–	–	463
2006/07	230	230	–	–	–	–	–	–	–	–	460
2007/08	224	233	–	–	–	–	–	–	–	–	457
2008/09	244	232	–	–	–	–	–	–	–	–	476
2009/10	247	259	–	–	–	–	–	–	–	–	506
2010/11	250	255	–	–	–	–	–	–	–	–	505
2011/12	250	262	–	–	–	–	–	–	–	–	512
2012/13	241	273	–	–	–	–	–	–	–	–	514
2013/14	251	260	–	–	–	–	–	–	–	–	511
2014/15	258	284	–	–	–	–	–	–	–	–	542
2015/16	265	291	–	–	–	–	–	–	–	–	556
2016/17	278	294	–	–	–	–	–	–	–	–	572
2017/18	259	301	–	–	–	–	–	–	–	–	560
2018/19	272	284	–	–	–	–	–	–	–	–	556
2019/20	288	281	–	–	–	–	–	–	–	–	569
2020/21	288	280	133	147	143	145	–	–	–	–	568
2021/22	292	256	123	138	142	145	–	–	–	–	548
2022/23	277	266	125	134	138	146	–	–	–	–	543
2023/24	252	271	123	126	135	139	–	–	–	–	523
2024/25	268	300	148	127	145	148	–	–	–	–	568
2025/26	263	310	150	149	132	142	–	–	–	–	573