St Johns Hill is a suburb of Whanganui, in the Whanganui District and Manawatū-Whanganui region of New Zealand's North Island.

St Johns Hill covers 2.25 km (0.87 sq mi) and had an estimated population of 3,360 as of June 2024, with a population density of 1,493 people per km.

Historical population

Year	Pop.	±% p.a.
2006	3,096	—
2013	3,144	+0.22%
2018	3,375	+1.43%
Source:

St Johns Hill had a population of 3,375 at the 2018 New Zealand census, an increase of 231 people (7.3%) since the 2013 census, and an increase of 279 people (9.0%) since the 2006 census. There were 1,386 households, comprising 1,497 males and 1,878 females, giving a sex ratio of 0.8 males per female, with 525 people (15.6%) aged under 15 years, 405 (12.0%) aged 15 to 29, 1,371 (40.6%) aged 30 to 64, and 1,074 (31.8%) aged 65 or older.

Ethnicities were 88.4% European/Pākehā, 10.0% Māori, 1.5% Pacific peoples, 5.2% Asian, and 2.3% other ethnicities. People may identify with more than one ethnicity.

The percentage of people born overseas was 18.6, compared with 27.1% nationally.

Although some people chose not to answer the census's question about religious affiliation, 40.5% had no religion, 48.8% were Christian, 0.8% had Māori religious beliefs, 0.7% were Hindu, 0.1% were Muslim, 0.5% were Buddhist and 1.4% had other religions.

Of those at least 15 years old, 630 (22.1%) people had a bachelor's or higher degree, and 528 (18.5%) people had no formal qualifications. 471 people (16.5%) earned over $70,000 compared to 17.2% nationally. The employment status of those at least 15 was that 1,137 (39.9%) people were employed full-time, 393 (13.8%) were part-time, and 87 (3.1%) were unemployed.

Individual statistical areas

Name	Area (km)	Population	Density (per km)	Households	Median age	Median income
St Johns Hill East	1.12	1,173	1,047	456	60.1 years	$24,400
St Johns Hill West	1.12	2,202	1,966	930	49.6 years	$29,400
New Zealand					37.4 years	$31,800

St Johns Hill School is a co-educational state primary school for Year 1 to 6 students, with a roll of 426 as of August 2024.

St Mary's School is a co-educational state-integrated primary school for Year 1 to 8 students, with a roll of 252.

Cullinane College is a co-educational state-integrated secondary school, with a roll of 441.

Rotokawau Virginia Lake, located on St John's Hill, is a historic lake with a fountain, Art Deco conservatory and winter garden.

• James K. Baxter, poet and playwright, attended St Johns Hill School in 1936
• Emily White started a garden on her large property on St Johns Hill in 1882; it gained international renown

• St John's railway station, 1881-1960