21 Riverside Ave
Mastic Beach, NY 11951
3 bd 3 ba 2,125 sqft Built 1957 Lot 10,890 sqft single_family
No recorded sales
Location
Timeline: Sale, Listing & Tax History
Recorded events
No recorded events
No sale or listing events are on file for this property.
Tax assessment history
| Year | Building | Land | Total assessed | Tax paid |
|---|---|---|---|---|
| 2025 | $2,460 | $150 | $2,610 | $10,841 |
| 2024 | $2,460 | $150 | $2,610 | $10,401 |
| 2023 | $2,460 | $150 | $2,610 | $11,731 |
| 2022 | $2,460 | $150 | $2,610 | $12,074 |
| 2021 | $2,460 | $150 | $2,610 | $12,017 |
| 2020 | $2,460 | $150 | $2,610 | $11,845 |
| 2018 | $2,460 | $150 | $2,610 | $11,596 |
| 2017 | $2,460 | $150 | $2,610 | $11,387 |
| 2016 | $2,460 | $150 | $2,610 | $10,613 |
| 2015 | $2,460 | $150 | $2,610 | $10,949 |
| 2014 | $2,800 | $150 | $2,950 | $8,316 |
| 2013 | $2,800 | $150 | $2,950 | $5,396 |
| 2012 | $2,800 | $150 | $2,950 | $7,700 |
| 2011 | $2,800 | $150 | $2,950 | $7,997 |
| 2010 | $2,800 | $150 | $2,950 | $7,897 |
| 2008 | $2,800 | $150 | $2,950 | $8,611 |
| 2007 | $2,800 | $150 | $2,950 | $8,084 |
| 2006 | $2,800 | $150 | $2,950 | $7,551 |
Property facts
Year built
1957
Property type
single_family
Stories
2
Beds
3
Baths
3
Living area
2,125 sqft
Lot size
10,890 sqft
ZIP code
11951
City
Mastic Beach
Street
Riverside Ave
Coordinates
40.78638, -72.83146
Comparable properties nearby
Block-level micro-comps
Same street, ±3 house numbers, sold in the last 24 monthsFrequently asked questions
When did 21 Riverside Ave last sell?
No public-record sale is on file for 21 Riverside Ave.
What is the current tax assessment for 21 Riverside Ave?
The most recent total assessment for 21 Riverside Ave (year 2025) is $2,610 with $10,841 in property tax.
When was 21 Riverside Ave built?
21 Riverside Ave was built in 1957.
How does 21 Riverside Ave compare to others on Riverside Ave?
We track 8 other properties on Riverside Ave. Browse the list under "Other properties on Riverside Ave" to compare beds, baths, and sale history.
What are the property facts for 21 Riverside Ave?
21 Riverside Ave is a 3 bed, 3 bath, 2,125 sqft, 10,890 sqft lot single_family.
Is 21 Riverside Ave a flip candidate?
No — 21 Riverside Ave does not appear in our flips dataset.
Is 21 Riverside Ave a tax-appeal candidate?
No — 21 Riverside Ave is not currently flagged as a tax-appeal candidate.
Forecast for this area
ZIP-area linear projection — not a per-property automated valuationQuarterly trend
+2.2%
Implied 1-yr
+8.8%
2026 Q2
$434.2K
2026 Q3
$442.6K
ZIP 11951 — Median Price History + Forecast
Explore nearby
Geography
Other properties on Riverside Ave