Is it Covered by Copyright?
U.S. Copyright law offers copyright owners protection for a specific amount of time. Some materials are in the public domain, which means the copyright term has expired or never existed and the intellectual property is not owned or controlled by any person or entity. There are some expressions, including facts, local laws, or works of the US Government (to name a few), which are excluded from copyright protections. These are born directly into the public domain, free to copy, reuse, adapt or distribute. Works in the public domain can be used freely, but you must still properly cite them.
Tools to help you determine if the item you wish to use is in the public domain: