The Department of Buildings keeps a record on sidewalk sheds and provides a great map to look at them. Central Harlem currently has 249 sidewalk sheds, whereas East Harlem has 202.

Mapped, the data shows that they are, pretty much, everywhere:

And, if you filter for 5 years or older! Here’s the map you get:

The size of the circles indicates how big/long the sidewalk shed is. The orange colors indicate that it’s in a commercial area whereas the blue ones are residential.

Here’s the link to explore for yourself:

https://www.nyc.gov/assets/buildings/html/sidewalk-shed-map.html