Riversdale is a suburb of Blenheim, in the Marlborough region of the South Island of New Zealand. Riversdale is separated from the rest of Blenheim by the Ōpaoa River on the north, east and western sides, and by the Main North Line and State Highway 1 on the western side. To the south, Islington is similarly separated on three sides by the Ōpaoa.

The Nelson Marlborough Institute of Technology has its Marlborough Campus in Riversdale.

Riversdale and Islington cover 1.10 km (0.42 sq mi). They had an estimated population of 2,550 as of June 2024, with a population density of 2,318 people per km.

Historical population

Year	Pop.	±% p.a.
2006	2,151	—
2013	2,070	−0.55%
2018	2,319	+2.30%
Source:

Riversdale-Islington had a population of 2,319 at the 2018 New Zealand census, an increase of 249 people (12.0%) since the 2013 census, and an increase of 168 people (7.8%) since the 2006 census. There were 852 households, comprising 1,179 males and 1,140 females, giving a sex ratio of 1.03 males per female. The median age was 38.3 years (compared with 37.4 years nationally), with 414 people (17.9%) aged under 15 years, 492 (21.2%) aged 15 to 29, 1,011 (43.6%) aged 30 to 64, and 402 (17.3%) aged 65 or older.

Ethnicities were 81.1% European/Pākehā, 20.7% Māori, 5.3% Pasifika, 6.2% Asian, and 2.6% other ethnicities. People may identify with more than one ethnicity.

The percentage of people born overseas was 17.1, compared with 27.1% nationally.

Although some people chose not to answer the census's question about religious affiliation, 56.8% had no religion, 30.8% were Christian, 1.3% had Māori religious beliefs, 0.4% were Hindu, 0.5% were Muslim, 0.8% were Buddhist and 2.2% had other religions.

Of those at least 15 years old, 186 (9.8%) people had a bachelor's or higher degree, and 456 (23.9%) people had no formal qualifications. The median income was $28,900, compared with $31,800 nationally. 156 people (8.2%) earned over $70,000 compared to 17.2% nationally. The employment status of those at least 15 was that 1,014 (53.2%) people were employed full-time, 255 (13.4%) were part-time, and 72 (3.8%) were unemployed.