Yes, it is illegal to place a paper or any other item that has not been mailed through the United States Postal Service (USPS) into someone else’s mailbox. This action violates federal law, specifically Title 18, United States Code, Section 1725, which states that only authorized mail, which has been processed by the USPS and for which postage has been paid, can be placed in or on mailboxes. The law is intended to protect the security and integrity of the postal service and the privacy of mailbox owners.

Violating this law can result in fines for each piece of unauthorized mail placed in a mailbox. This rule applies to flyers, brochures, letters, and any other materials, regardless of the intention behind them, whether it be advertising, community announcements, or personal messages.

For those looking to distribute materials directly to homes or businesses without using the USPS, alternatives include…

1. Door Hangers – Placing advertisements or information on door hangers that can be hung on doorknob handles.
2. Direct Mail – Using USPS services to send materials directly to addresses, ensuring that postage is paid and the distribution is legal.
3. Personal Delivery – Handing materials directly to recipients, provided that it is done in a manner that respects local solicitation laws and property rights.

Always respect privacy and legal boundaries when distributing materials to ensure compliance with laws and maintain positive relationships within the community.