If a US government website is hacked who do I report it to?

[Underdog]

Try the FBI. If they don't handle that kind of thing, they can probably refer you to somebody that can.

[n567]

Within the website there should be an email address for the website's administrator (usually at the bottom of the page). They would be the best to inform. usually the address is simple. [email protected], for example...

[Kotonk]

Anyone know?