This is a bonus entry, since it isn't a bridge by the terms I've set out for myself, but a viaduct. In other words, it doesn't go over a body of water but connects two hills on either side of what is known as Manhattan Valley roughly at 125th St. I decided to do a report on this viaduct since it's a good size and significant, and it's got aesthetic value, particularly from underneath, and it's a good place to run.
The viaduct itself carries Riverside Drive across the Manhattan Valley from just north of 122 St. at the General Grant National Memorial (Grant's Tomb) to 135 St. It has four wide lanes of traffic as well as parking lanes and sidewalks on both sides. There's plenty of room to run or walk, as it does have a lot of pedestrian traffic, and the roadway even has plenty of room for cyclists, even without bike lanes. But it should be noted that the sidwalks are almost never cleared of snow in the winter. The viaduct is good for runners, as you can run along the west sidewalk of Riverside Drive, usually alongside Riverside Park, without having to cross any streets between 95 St. and just north of 165 St.
Directly underneath the viaduct is 12th Ave, from St. Clair Place to 135 St. 12th Ave. itself is a horrible place to run, since there's a lot of traffic, and the sidewalks are taken up by forklifts and the bike lane usually taken up by delivery trucks for Fairway grocery store. Fortunately, last year Harlem Piers Park opened a block to the west, right along the river, connecting the Cherry Walk to the south with a dedicated bike lane and sidewalk leading to Fort Washington Park to the north. This enables a runner to run traffic-free directly along the river from the midtown piers to Dyckman St. That option doesn't involve running on the viaduct, but it's good that runners have those options.
Prior to the viaduct, Riverside Drive ran only from 72 St. to the loop around the current location of Grant's Tomb (completed 1897) and Claremont Dolphin Playground, the northern tip of which is as far north as nearby Tiemann Place (then 127 St.). Where the playground is now, there used to be located the Claremont Inn, a hotel with some big names among its customers. An eastern branch of Riverside Drive also continued, as it still does, downhill from about a block north of 122 St. down to St. Clair Place. In 1897 a bond issue passed to permit the continuation of Riverside Drive north to 157 St. and connect to Boulevard Lafayette (which would be renamed Riverside Drive as well). This extension would require construction of the viaduct, which was completed in 1900. The city council wanted to pass the bond issue in 1897 before the 1898 consolidation with the other boroughs into Greater New York, since the other boroughs had more debt and the bond issue might not have passed after consolidation. The history and development of Riverside Drive/Boulevard Lafayette/Henry Hudson Parkway is fascinating, and may be the subject of another post after I'm done with my bridges.
Pictures: 1. Underneath the viaduct, looking south along 12th Ave. from 135 St.; 2. Looking north on the west side of the viaduct; 3. Looking north from Claremont Dolphon Playground.