If you take a look in Google Groups, you will find tons of people over the last year who have asked a question similar to this:

"How do I use forms authentication on a subfolder in my ASP.NET project?"

And more often than not, the answer is the same. Most people will tell you to create a separate web.config file for that directory. I don't like this for two reasons:

1. I have to create a new Application in IIS.
2. I have 2 web.config files to manage.

Sometimes you can't create a new web application (think shared hosting), and maintaining more than one web.config is annoying. My answer is this...

Add a <location> section to the bottom of your existing web.config like this:

 <location path="Admin">
  <system.web>
   <authorization>
    <allow users="Administrator" />
    <deny users="*" /> 
   </authorization>
  </system.web>
 </location>

Basically what this does is create a new little web.config for a particular folder, in this case ~/Admin/. Now you can set the same config values you would have used for the main web. In this example, we have configured the <authorization> element to allow the Administrator user, but to deny the Anonymous user (*).

Much easier to do that creating a whole new config.