Why is Washington DC called the Beltway?

The term Beltway is used to describe the activity of the political establishment concentrated in Washington, DC, such as US federal government officials, lobbyists, consultants, and media commentators.

The term comes from Interstate 495 highway, known as the Capital Beltway, which encircles Washington, DC.

Inside the Beltway is a common term used to describe political activity that occurs within the US capital as distinct from the rest of the country.