[Update: June 5, 2010: In January, an armed robber held up a jewlery store on Madison Avenue between 75th an 76th, shooting and killing a 71-year old employee. This is the first shooting homicide in the Upper East Side in over seven years, and per the linked-to article, seemingly random.]

The New York Times came out with a neat interactive map of homicides in New York City — something which would be really cool if it were not about murder. According to the map, ove the six and a half year period covered (2003 to present), NYC recorded just over 3,400 homicides, of which 15% — or about 500 — were in Manhattan.

The Upper East Side section of Manhattan is incredibly safe, apparently. 11 homicides over the period, or about two per year. For an area with a population of 200,000+, that gives roughly a 1 homicide per 100,000 per annum. To put that in perspective, in 2003, Maine had the “best” homicide rate in the nation, at 1.2 per 100,000.

There are no formal barriers separating the Upper East Side from the rest of Manhattan — yes, it abutts Central Park on the west but one can easily walk though that, and the east is bound by the East River. North and south, though, the lines are 96th and 59th streets respectively, which is to say, the borders are entirely fluid with the neighborhoods next to them. (A guess as to why the lines are where they are? On the south side, Central Park ends on 59th; on the north, the Metro North train tracks come above ground at 97th.) The borders are known but hardly observed in any true fashion — we regularly consider a playground on 99th and 5th to be in the “Upper East Side”, for example.

If you live here, you probably will understand why the neighborhood is safer than most, but experience does not translate well to words. I was not terribly surprised to see a low homicide rate, although admittedly it was much lower than I expected. What did surprise me, however, was one simple fact: no firearms were used in the homicides. Or, more accurately, guns abide by the borders.

The map above sums it up. The green dots — firearm-related homicides — all fall outside the borders of the Upper East Side. There are two which are close, of course: 57th and Madison, 97th and 3rd. Two blocks south of the UES, one block north. This makes the UES a massive outlier, as 69% of the 3,400+ homicides city-wide were firearm-related.

Why?