Reveal the IDs without a plugin

In your WordPress admin backend goto “Posts > Categories” and mouse over the category you want to find the ID for. When your mouse pointer is on the category name, have a look into the status bar of your browser. You will see an URL that ends with something like &cat_ID=6 (or another number). In this case “6″ is the ID for the selected category and you can put it in the Optionspanel of the theme where you need it (e.g the leadarticle)

Use a plugin to reveal the IDs

As in many cases you can also use a plugin to do the job for you. The Plugin is called “Reveal IDs for WP Admin“. There is not much to say about it because all it does is to show the IDs next to the category name. It can also display the IDs for Posts, Pages etc. Very handy.

See the screenshot for details of the browser status bar and the rvealed IDs with the plugin in use