21 Riverside Avenue
Description
- Listed by: Lawrence M Gardner • Exit Realty All Pro 631-647-8844
Recent comparable sales
Median sold price
$550,000
Avg days on market
26
Sale-to-list ratio
107.7%
Mastic Beach, NY
9 comparable properties found
$583,000
Sold 08/21/25
- 3
- Bedrooms
- 3
- Bathrooms
- 1,900
- Square Feet
- 0.23
- Acres
$550,000
Sold 05/13/25
- 3
- Bedrooms
- 3
- Bathrooms
- 1,808
- Square Feet
- 0.21
- Acres
$535,000
Sold 05/07/26
- 3
- Bedrooms
- 3
- Bathrooms
- 1,850
- Square Feet
- 0.18
- Acres
$560,000
Sold 09/17/25
- 3
- Bedrooms
- 3
- Bathrooms
- 1,600
- Square Feet
- 0.17
- Acres
$529,000
Sold 12/30/25
- 3
- Bedrooms
- 2
- Bathrooms
- 2,224
- Square Feet
- 0.33
- Acres
$565,000
Sold 07/23/26
- 3
- Bedrooms
- 3
- Bathrooms
- 1,479
- Square Feet
- 0.55
- Acres
$475,000
Sold 04/03/25
- 3
- Bedrooms
- 2
- Bathrooms
- 2,300
- Square Feet
- 0.14
- Acres
$610,000
Sold 09/17/26
- 4
- Bedrooms
- 3
- Bathrooms
- 2,100
- Square Feet
- 0.27
- Acres
$465,000
Sold 12/23/24
- 3
- Bedrooms
- 3
- Bathrooms
- Unavailable
- Square Feet
- 0.23
- Acres
Location
Sold By Exit Realty All Pro, Lawrence M Gardner
Payment Calculator
$3,707 per month
30 year fixed, 7.03% Interest
$2,701
$1,006
$0
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1Property Information for 21 Riverside Avenue
- Taxes: $12,074 / year
- MLS Type: Single Family
- County: Suffolk County
- Township: Brookhaven
- View: Panoramic, River, Water
- Architectural Style: Farmhouse
- Community Features: Park, Near Public Transportation
- Garage Spaces: 2.0
- Waterfront: true
- Section Area: Woodcut Dr
- Offer Presentation: Cannot be Present
- Year Built: 1957
- Lot Size: 0.25 AC / 10,890 SF
- Senior Community YN: No
- MLS Area Minor: 25
- MLS District Code: 200
- Directions: Mastic Rd to Madison, to Riverside Ave #21
- Tax Block: 0001
- Tax Lot: 22
- Property Attached: No
- Structure Type: Detached
- Levels: Two
- New Construction YN: No
- Flood Zone Report: Yes
- Flood Zone Date: 10-31-2022
- Square Footage Source: Municipality
- Lot Size Source: Other
- School District: William Floyd
- Elementary School District: William Floyd
- Elementary School: William Floyd Elementary School
- Middle Or Junior School District: William Floyd
- Middle Or Junior School: William Floyd Middle School
- HighSchool District: William Floyd
- High School: William Floyd High School
- Lease Considered: No
- Building Units Total: 1
- Room Level: Second
- Room Type: Kitchen
- Room Description: Expanded Eat in Kitchen with Granite Countertops and iUpdated appliances. Master Suite
- Room Level: First
- Room Type: Family Room
- Room Description: Bedroom. Full Bath, Family Room, Extra Room, Heated 2 Car Garage
- Parcel Number: 0200-940-00-05-00-022-000
- Tax Map Number: 0200-940-00-05-00-022-000
- Included In Taxes: Trash
- Amenities: 1st Floor Bedrm, A/C Units, Bulkhead, Central Vacuum, Creek, Den/Family Room, Dishwasher, Dryer, Eat in Kitchen, Entrance Foyer, Formal Dining Room, Granite Counters, Hardwood Floors As Seen, Home Office, Master Bath, Microwave, Near Public Transportation, Panoramic, Park, Powder Room, Private Entrance, Public, Refrigerator, River, Storage, Walk In Closet, Washer, Water Access, Water View, Waterfront
- Interior Features: 1st Floor Bedrm, Den/Family Room, Eat-in Kitchen, Formal Dining Room, Entrance Foyer, Granite Counters, Home Office, Master Bath, Powder Room, Storage, Walk-In Closet(s)
- Appliances: Dishwasher, Dryer, Microwave, Refrigerator, Washer
- Number Of Kitchens: 1
- Total Rooms: 10
- Living Area: 2125.0
- Living Area Units: Square Feet
- Basement: None
- Attic Description: None
- Fireplace: Yes
- Fireplaces Total: 1
- Location Amenities: Near Public Transportation, Hardwood Floors As Seen, 1st Floor Bedrm, Library Den, Eat in Kitchen, Formal Dining Room, Entry Foyer, Foyer, Granit Countertops, Home Office, Master Bath, Powder Room, Storage, Walk In Closet, Open View, River, River Views, Water View, Water Access
- Common Walls: No Common Walls
- Flooring: Hardwood
- Exterior Features: Private Entrance, Bulkhead
- Exterior Property Features: Private Entrance, Bulkhead, Private, Attached, 2 Car Attached, Driveway, Park, Near Public Transportation
- Elevation Certificate: No
- Construction Materials: Frame, Vinyl Siding
- Waterfront Features: Creek, Water Access, Waterfront
- ViewYN: Yes
- Lot Size Dimensions: .25
- Site Features: Park, Near Public Transportation
- Building Area Units: Square Feet
- Parking Type: Pvt
- Parking Features: Private, Attached, 2 Car Attached, Driveway
- Attached Garage: Yes
- Garage: Yes
- Cooling: Yes
- Cooling: Central Air
- Heating: Oil, Baseboard
- Heat Fuel Type: Oil, Baseboard, Electric Stand Alone
- Number of Heating Zones: 2
- Separate Hot water Heater Detail: y
- Hot Water: Electric Stand Alone
- Sewer: Public Sewer
- Water Source: Public
- Green Features: Dishwasher, Dryer, Microwave, Refrigerator, Washer, Oil, Baseboard, Electric Stand Alone, Private Entrance, Bulkhead
- Virtual Tour URL Unbranded: https://my.matterport.com/show/?m=BVZHSsA4GD3&mls=1
Property History for 21 Riverside Avenue
| Date | Event & Source | Price | Appreciation |
|---|---|---|---|
| Jul 25, 2014 | Sold (Public Record) Public Record #432656510 | $250,000 | — |
| Date | Event & Source | Price |
|---|---|---|
| 07/25/2014 | Sold (Public Record) Public Record #432656510 | $250,000 |
For completeness, we often displays two records for one sale: the MLS record and the public record.
Public Records for 21 Riverside Avenue
Schools near 21 Riverside Avenue
Rating | School | Type | Grades | Distance |
|---|---|---|---|---|
| Public - | K to 5 | |||
| Public - | 6 to 8 | |||
| Public - | 9 to 12 | |||
| Public - | K to 5 |
Rating | School | Distance |
|---|---|---|
Tangier Smith Elementary School PublicK to 5 | ||
William Paca Middle School Public6 to 8 | ||
William Floyd High School Public9 to 12 | ||
William Floyd Learning Center PublicK to 5 |
School ratings and boundaries are provided by GreatSchools.org and Pitney Bowes. This information should only be used as a reference. Proximity or boundaries shown here are not a guarantee of enrollment. Please reach out to schools directly to verify all information and enrollment eligibility.
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Nearby home values
| Address | Sold price | Beds | Baths | Sqft | Lot (Sqft) |
|---|---|---|---|---|---|
This home: 21 Riverside Avenue, Mastic Beach, NY 11951 | $506,000 | 3 | 3 | 2,125 | 10,890 |
$582,500 | 3 | 3 | 1,700 | 10,890 | |
$629,000 | 4 | 3 | 2,400 | 10,890 | |
$210,000 | 3 | 1 | 1,400 | 21,780 | |
– | – | – | – | 10,890 | |
$280,000 | – | – | – | 10,019 | |
$650,000 | 4 | 4 | 3,905 | 16,553 | |
– | – | – | – | 10,019 | |
$85,000 | 3 | 1 | – | 33,105 | |
– | – | – | – | 16,553 | |
$173,000 | 2 | 1 | – | 21,780 | |
$151,500 | 3 | 1 | – | 10,890 | |
– | – | – | – | 10,890 | |
$475,000 | 4 | 2 | – | 28,750 | |
$150,000 | 2 | 2 | – | 25,264 | |
– | – | – | – | 16,117 |
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No guarantee, warranty or representation of any kind is made regarding the completeness or accuracy of any information, descriptions or measurements (including square footage measurements and property condition), such should be independently verified through appropriate means, including, but not limited to, in person inspection and public records, and Compass International Holdings, its subsidiaries, affiliates and independently owned and operated franchisees, and their affiliated agents and associated third parties expressly disclaim any liability in connection therewith. Photos may be virtually staged or digitally enhanced and may not reflect actual property conditions. Offers of compensation are subject to change at the seller's discretion. No financial or legal advice provided. Equal Housing Opportunity. Subject to change at any time. Compass, Inc., its subsidiaries, affiliates and their agents and associated third parties make no guarantee, warranty or representation regarding the accuracy of any waterfront feature, water view or waterfront view.
Listing Courtesy of Exit Realty All Pro, Lawrence M Gardner
The source of the displayed data is either the property owner or public record provided by non-governmental third parties. It is believed to be reliable but not guaranteed. This information is provided exclusively for consumers’ personal, non-commercial use. The data relating to real estate for sale on this website comes in part from the IDX Program of OneKey® MLS. Information Copyright 2026, OneKey® MLS. All Rights Reserved.