- Year built
- 1899
- Type
- Cooperative
- Amenities
- Central air, in-home laundry and private garden with the lower duplex
- Landmark status
- Not an individual landmark; not in a historic district
- NYC Landmarks Preservation Commission and City Planning records, updated February 2026
Own an apartment here? See what it would sell for.
A Private Pricing Opinion — what your apartment at 421 Fourth Street would likely sell for today, what it costs to sell, and what you’d walk away with — reviewed personally against condition, exposures, renovation quality, and the competition actually on the market.
About the building
421 Fourth Street is a three-residence cooperative in a Park Slope townhouse. PLUTO dates the building to 1899. It occupies a lot of approximately 1,900 square feet, with about 3,380 square feet of building area across its principal floors. The cooperative is outside an LPC-designated district, and DOF places it in Class 2C despite its small number of residences.
The lower home is a three-bedroom, two-bathroom duplex entered at the parlor level. High ceilings, a bay window and preserved wood trim remain part of its interior. A private backyard serves the duplex, which also has central air and in-home laundry. The two-level plan connects its principal living space to the lower rooms through an interior stair, while the other residences occupy the upper portion of the building.
Building staffing and amenities
- Elevator
- NoSource: NYC Department of City Planning records (PLUTO)
- Amenities noted
- GardenSource: The Roebling Team's building profile
Staffing and amenities as our building profile and recent listing records describe them. A feature not listed is not confirmed absent. Outdoor space, parking and some facilities can belong to particular apartments or to a separate owner; confirm access for the specific apartment.
Local Law 97
This building is below the 25,000 sq ft threshold at which LL97 limits apply to a building on its own. It is still covered if it shares a tax lot or condominium board with buildings totaling over 50,000 sq ft; confirm on DOB’s covered-buildings list.
See full Local Law 97 analysis →Recent sales
Recent transfers at this building, from The Roebling Research Library. Prices are the transfer amounts recorded with the NYC Department of Finance; apartment-level detail is checked against the building’s own file in The Roebling Research Library before publishing.
| Date | Unit | Apartment | Price | PPSF | vs. Ask |
|---|---|---|---|---|---|
| Oct 23, 2025 | 1 | 3 BR · 2 BA · 1,575 sf | $2,150,000 | $1,365/sf | +13.5% |
Market read. Most recent trades (2025) cleared a median $1,365/sf (recorded) across 1 sale.
Sales sourced from NYC Department of Finance recorded transfers (BBL 3-00983-0059). Apartment-level facts (line, condition, asking-price context) curated and cross-verified in The Roebling Research Library. Not all transactions cross-verify with ACRIS records — sponsor and LLC purchases sometimes record at stipulated values rather than market price; square footage on co-ops is not officially recorded, figures shown are approximate.
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Buying here? Co-op closing costs typically run 2 to 3% of the price. See NYC co-op and condo closing costs, line by line.
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What to know if you’re buying
Three homes fund the cooperative. The duplex's garden is a private-use amenity, while the roof, exterior walls and building insurance remain matters for the corporation. The proprietary lease and share allocation determine each home's financial obligations. With only three shareholders contributing, an exterior repair can require a sizable contribution from each, and a buyer's lender must approve this small cooperative as well as the individual loan.
Comparable buildings
- 240 8th Street — another small prewar cooperative with a larger shareholder group.
- 459 12th Street — low-rise cooperative housing farther south in Park Slope, with more homes sharing expenses.
- 904 Union Street — an older small cooperative north of this address, useful for comparing building scale and shared costs.
More Park Slope buildings
- 415 9th Street — 1912 co-op
- 418 17th Street — 1920 condominium
- 420 12th Street (Ansonia Court) — 1880 co-op
- 422 Second Street — 1920 co-op
- 423 15th Street — 1909
- 426 2nd Street, 426 2nd Street · Park Slope — 1920 condominium
The neighborhood
For the full neighborhood — its buildings, character, and market — read The Roebling Team Guide to Park Slope.
The full playbook — what goes in the package, how boards read your financials, the interview, and the timeline — plus sample cover, reference, and personal letters you can adapt.
How to read the facts on this page. Items attributed to an offering plan describe the building as it was offered at that filing — unit mix, square footage, the amenity program as planned. They are not a statement about how the building operates today. Tax and compliance figures are sourced separately to current City records and carry their own dates. House rules, staffing and fee policy can change by board resolution without any public filing: treat every policy line here as a starting point for diligence and confirm it with the managing agent. Where this page compares one building or neighborhood to another, that is our analysis of the recorded record — it names the measure, the period and the sample it rests on, and it is an observation about medians rather than a prediction about any particular apartment.
Considering a move at 421 Fourth Street?
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646.939.7375 · c.cohen@compass.com