Hi, and welcome to DC!
I just moved back myself last month (I grew up here, spent last 5 years in Philly/Chicago).
NW DC is FABULOUS for running. Lots of Trails. Rock Creek Park is a very large forrested park with many trails, some paved, most not. You can find all kinds of terrain, and some serious hills if you want them, or stick to the Valley where it's flat. They even close off some of the roads all weekend to facilitate recreational users. I ran a 9 mile loop this morning all on trails, w/o covering the same ground twice. Only 2 significant street crossings. Saw 3 deer, and about a dozen other runners.
A little to the West is Glover Arcbold Park, with a 3.1 mile unpaved trail and Battery Kemble Park, with maybe a 3 mile loop trail.
The great thing is that these trails all interconnect and all have access to the Towpath, Mall, Haines Point, and other areas that are great for running.
There are lots of runners in DC. Head down to the towpath or the Mall in the early morning and they are everywhere.
Traffic can be brutal during rush hours, which is one of the reasons I like to run in Rock Creek Park, but doesn't deter running at other times and most areas of NW have wide sidewalks that accomodate runners well.
Overall I would say it is very safe, although as with any city you should be aware when running alone or at night. Most areas of NW are very tame though, so I wouldn't worry.
What school are you attending? Do you know where you are living? Again, welcome to DC, I obviously could not be more enthusiastic about the running scene, and good luck w/ school!
-Scott C.
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Play hard.
http://This message has been edited by VeganPride (edited Jun-29-2005).