How do I completely uninstall Google Chrome and Chromium?

Note: this recipe has been updated in 2020 to more safely backup the files rather than using a recursive delete.

To uninstall Chromium Browser, run these commands from your terminal:

$ sudo apt-get purge chromium-browser
$ mv ~/.config/chromium/ ~/.config/chromium.bak/

To uninstall Google Chrome, run these commands from your terminal:

$ sudo apt-get purge google-chrome-stable
$ mv ~/.config/google-chrome/ ~/.config/google-chrome.bak/

In both examples, the first command removes the package while the second command will move custom settings, such as plugins, to a backup directory.

For Google Chrome:

Deleting ~/.config/google-chrome (where ~ is your home directory) should be sufficient. Why don't you try it and see? (Of course, this will delete all your bookmarks too.)

If that's not sufficient, you may want to also remove Google Chrome from the Terminal using the sudo apt-get purge ... command (where ... is replaced by the package you want to remove or a space-separated list of the packages you want to remove), or remove it in the Synaptic Package Manager (which you can install in the Software Center if you don't have it; it's itself provided by the package synaptic) by right-clicking on the packages you want to remove and clicking "Mark for Complete Removal". These ways of removing packages will remove all global (i.e., non-user-specific) configuration files.

For Chromium (the completely open source counterpart to Chrome):

You can do it the same way, just delete ~/.config/chromium. You can also remove the package as mentioned above for Google Chrome. The package that provides Chromium in Ubuntu is called chromium-browser.

I successfully removed Google Chrome by running the following command:

sudo apt-get purge google-chrome-stable