The East River Greenway, a segment of the Manhattan Waterfront Greenway, is a shared pedestrian and bicycle path that runs along the East Side of Manhattan from the Battery to East Harlem with a 1.2 mile gap from East 37th to East 60th streets in Midtown. Portions of the Greenway are narrow and unsafe due to sinkholes being blocked off by protective fencing, and one part squeezes between the FDR and a Con Ed ship dock, requiring caution and slower speeds. Other parts are shared space with vehicles access alongside Waterside Plaza or a filling station.

Check out the NYC DOT 2010 Bicycle Map (pdf)

Read more about NYC Greenways on the NYC Parks Department web-site.