The folder, quite obviously, is property of the root user, which is why you have to use sudo in order to interact with the folder. I don't think chown is able to apply permission changes to a folder, so you would have to go for the graphical route, as explained below.

[EDIT] A folders location typically doesn't affect it's permissions level or owner. For example, I could be the owner of a folder sitting in /usr/share/, but root could be the owner of a folder on my desktop. If you're wondering why it is this way, I'd say ask Bell Labs. They started it. :)

(I used Nemo, but the steps are the same for Nautilus)

First, open a terminal and type sudo nautilus (again, I used Nemo, but it's the same procedure), and enter your sudoer's password.

When Nautilus opens, navigate to the folder you wish to change permissions on. Depending on what program you use, you may see and "Elevated Privileges" notice. This is to remind the user to be careful with what they do, as root permissions could damage the computer if used the wrong way.

Now right click the folder you want to change and choose "Properties" go to the "Permissions" tab, and it should look something like this:

Select the dropdown menu for Owner and Group, and change them from "root" to your username (in my case, ben). It should look like this now:

If desired, click "Apply Permissions to Enclosed Files". Then close Nautilus and exit the terminal.