Where is the applicationHost.config file for IIS?

On newer versions of IIS (v. 7.0 and later), the applicationHost.config file contains all of the XML values for the IIS configuration.

This can be found at the following location: C:\Windows\System32\inetsrv\config\applicationHost.config

If you are looking for the applicationHost.config for IIS Express, you can find that here:  C:\Users\<User Profile Name>\Documents\IISExpress\config\applicationhost.config