In my neighborhood, the threat is pitbulls. People keep them on a leash, but those dogs a strong and toy breeds look like snack food to them, and I've heard stories.
An infrequent threat are dog nappers; there have been four incidents I know about in the last two years. They target fluffy toys and pitbull puppies and will rob you of your dog. DC residents love their dogs, so the police and media have these incidents all over tv, and got back 3 of the 4 stolen by robbery.
As a result of the above, on the few occasions I have taken Bella out, it's 2 miles away at the Nation's Capitol / Capital Hill (bunch of foo-foo and designer dogs there) or to my daughter's place in a nicer part of DC, or down to my brother's near Solomon Islands. (He's doing fine, btw, and hasn't had a recurrence of cancer.)
Until I retire (possibly this summer), I'll remain in my neighborhood; it's got it's rough spots but is in transition, and the building is very nice with a nice view and I'm only a few minutes away from the school where I work. I'd like to move near my brother's house in Maryland which is walking distance from the beach. Birds of prey could be a concern.
Owls, hawks, coyotes, pits, thugs, etc. It seems that where ever you live, there's something to be careful about if you have a pretty or small dog.