Trapped Inside the Beltway - 2013 was released on:

USA: 15 December 2013 (limited)

Dateline NBC - 1992 Inside the Beltway was released on:

USA: 14 September 1998

Inside Outside the Beltway - 1992 was released on:

USA: 20 September 1992 (Washington, D.C.)

The Capital Beltway is located in Washington, D.C. It is the basis of the phrase Inside the Beltway, used when referring to issues dealing with American government and politics.

I'm pretty sure it's short for "Beltway," as in "Inside the Beltway" of Washington DC where most political/government action takes place.