Irwell was a small rural township in Canterbury, New Zealand on the intersection of Leeston and Selwyn Lake Roads. All that remains are the former school hall, a church, and a small number of houses.

In the 1870s it consisted of a two stores, two bake houses, a flour mill, a hotel, and a blacksmiths. In 1879 a small school was established with 32 pupils. By the 1920s it had 50 pupils. The school was closed at the end of 1937 and merged with Leeston School. In 1944 the Ellesmere Guardian reported that the old mills at Irwell were one of the few early buildings still standing in area.

Two buildings at Irwell are listed as heritage sites in the Selwyn District Plan. They are the former Irwell school hall from 1879 and St Mary's Anglican Church on Selwyn Lake Road from 1895.

Irwell statistical area, which also includes Doyleston and Selwyn Huts, covers 128.15 km (49.48 sq mi). It had an estimated population of 1,390 as of June 2024, with a population density of 11 people per km.

Historical population

Year	Pop.	±% p.a.
2006	1,182	—
2013	1,275	+1.09%
2018	1,278	+0.05%
Source:

The statistical area had a population of 1,278 at the 2018 New Zealand census, an increase of 3 people (0.2%) since the 2013 census, and an increase of 96 people (8.1%) since the 2006 census. There were 513 households, comprising 681 males and 597 females, giving a sex ratio of 1.14 males per female. The median age was 44.6 years (compared with 37.4 years nationally), with 222 people (17.4%) aged under 15 years, 186 (14.6%) aged 15 to 29, 672 (52.6%) aged 30 to 64, and 198 (15.5%) aged 65 or older.

Ethnicities were 92.7% European/Pākehā, 9.9% Māori, 1.4% Pasifika, 2.6% Asian, and 1.9% other ethnicities. People may identify with more than one ethnicity.

The percentage of people born overseas was 14.6, compared with 27.1% nationally.

Although some people chose not to answer the census's question about religious affiliation, 54.9% had no religion, 33.1% were Christian, 0.7% were Hindu, 0.5% were Buddhist and 1.4% had other religions.

Of those at least 15 years old, 183 (17.3%) people had a bachelor's or higher degree, and 198 (18.8%) people had no formal qualifications. The median income was $37,300, compared with $31,800 nationally. 165 people (15.6%) earned over $70,000 compared to 17.2% nationally. The employment status of those at least 15 was that 609 (57.7%) people were employed full-time, 168 (15.9%) were part-time, and 12 (1.1%) were unemployed.