What does Public Domain mean?

“Intellectual property rights which are not owned or controlled by anyone. The term indicates that these materials are therefore "public property", and available for anyone to use for any purpose”
- Wikipedia

Where can I find Public Domain Photography Websites?

Public Domain Pictures.net
http://www.publicdomainpictures.net/

The pictures are free for you to use, however, if your planning for commercial use, please be aware that no model release was obtained and pictures featuring products or property should be used with care.

Public-Domain-Photos.com
http://www.public-domain-photos.com/

All photos on this web site are public domain. You may use these images for any purpose, including commercial.

Burning Well.org
http://www.burningwell.org/

The images in the BurningWell repository are in the public domain. Basically, this means that you are allowed to use the images freely for any purpose, commercial or private. You do not have to pay to use them, or even acknowledge or give credit to the BurningWell repository or original photographer.

Flickr – Creative Commons
http://www.flickr.com/creativecommons/

The photos listed under the Attribution section allows you to copy, distribute, display, and perform your copyrighted work - and derivative works based upon it - but only if they give you credit
The photos listed under the Share Alike section allows others to distribute derivative works only under a license identical to the license that governs your work.

PDPhoto.org
http://pdphoto.org/index.php

Photographs may be freely used by everyone. Unless something is clearly marked as being something other than public domain, you can assume it is free to use.

These websites and blubs I’ve added under each one are taken directly from their website. As I find more, I’ll be added more.

Note: The information is accurate at time of posting, please check with the website, to ensure that the requirements of usage have not changed.

Note: The public domain photograph shown is called, "Sunset In Serengeti", shot by Richard Spencer