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684 3rd Avenue

Manhattan · East Midtown-Turtle Bay, NY 10017

684 3rd Avenue is a 24-apartment building in East Midtown-Turtle Bay, built in 1900, managed by Cornerstone MGMT Systems INC. The City has 14 open housing-code violations on file for it, one of them immediately hazardous, about 0.58 per apartment, roughly three times the neighborhood norm for a building this size (HPD, as of 5 October 2026). No tenant has reviewed it here yet. Everything above comes from the City's own records.

Managed by Cornerstone MGMT Systems INC

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Units
24
Year built
1900
Borough
Manhattan

This building’s record with the City

Complaints tenants filed with 311, and repairs a City inspector has asked for. Most repairs are routine maintenance. Both describe the building rather than the people in it, and often predate the current management.

3.0/5About average for the areaScored from the records below against every building we cover. It is not a tenant rating. Nobody who lived here said this.

0tenant complaints

Filed with 311 in the past year

14open repairs

Outstanding with HPD · about 0.6 per apartment

Immediately hazardous
1
Hazardous
9
Non-hazardous
4

What the open repairs are about

  • Stairs, floors and ceilings8
  • Pests2
  • Electrical1
  • Smoke and CO alarms1
  • Leaks, damp or mould1
  • Doors, windows and locks1

Source: NYC 311 and Housing Preservation & Development. Look this building up · updated Oct 2026

The company that manages it, elsewhere

Cornerstone MGMT Systems INC manages 97 other buildings we cover, holding 1,195 apartments.

open violations
213open violations
immediately hazardous
56immediately hazardous
311 complaints
40311 complaints

in the past year

per apartment
0.2per apartment

The company’s record across its other buildings, not this building’s. A company can run one well and another badly, and these figures often predate the current management. (HPD and 311, as of 5 October 2026.)

What tenants say

Nobody has written about 684 3rd Avenue yet.

Does the heat hold in January? How long does the super take? Does management answer the phone, and were you charged what you expected? No public record answers any of that. Only someone who lived here can.

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