The four distance zones commonly observed by North Americans, as specified by Edward T. Hall in 1966, are intimate distance, personal distance, social distance, and public distance. Of these four zones, public distance is the largest, ranging from twelve to twenty five feet.

As outlined on the website Creducation.net, the intimate distance zone is the smallest, ranging from 0 to 18 inches. This is the distance that is comfortable for embracing, touching, and whispering. The personal distance zone ranges from 18 inches to 4 feet and is the distance that is comfortable for conversations and interactions with close friends and family members.

According to the website AspenGroup.com, the social distance zone is the third-largest distance zone, with a range of 4 to 12 feet. This is the distance that is comfortable for conversations with acquaintances, strangers, and coworkers. Finally, the public distance zone, as outlined on the website Wikipedia.org, is the largest of the four zones, with a range of 12 to 25 feet. This is the distance that is comfortable for public speaking and gatherings.

In conclusion, of the four distance zones defined by Edward T. Hall in 1966, the public distance zone is the largest, with a range of twelve to twenty five feet. This is the distance that is comfortable for public speaking and gatherings.