LGA Arrivals Over Manhattan

[Speedbird1]

I often see LGA arrivals pass low over Manhattan. They fly south over Midtown and then circle into the Expressway/Visual Rwy 31 Approach, usually over Brooklyn. What's strange is that all these inbounds appear to be from BOS. Is there a special agreemnet allowing BOS inbounds to over-fly Midtown?

[AirtrafficController]

Well its not limited to aircraft coming in from Boston but more generally aircraft coming in from the North (New England, upstate NY, Canada, etc.) For the most part they cannot come in from the east (Long Island) to land on 31 while the Expressway Visual is in use so they fly over Manhanttan as you explained. All other aircraft use the normal approach to 31.