The license under which the WordPress software is released is the GPLv2 (or later) from the Free Software Foundation. A copy of the license is included with every copy of WordPress, but you can also read the text of the license here.
Part of this license outlines requirements for derivative works, such as plugins or themes. Derivatives of WordPress code inherit the GPL license. Drupal, which has the same GPL license as WordPress, has an excellent page on licensing as it applies to themes and modules (their word for plugins).
America's Tent Lodges has developed the complete content of the website by our own staff by use of the Wordpress software and plugins. All images and graphics are either property of America's Tent Lodges or are used with consent of the owner. There is no use of any material on which is a copyright.