The Nationwide insurance headquarters are located in Columbus at the following address: Nationwide World Headquarters, One Nationwide Plaza, Columbus, OH 43215–2220. This address can be found on the Nationwide website. The headquarters address can be used to send any correspondence via letter, but it is worth bearing in mind that mail is the slowest form of communication. Therefore, if you want to make a claim or have an urgent question then you would receive a more prompt response from phoning the company or even emailing them. The cost of postage would be about the same as the cost of a phone call, making emailing the cheapest form of communicating with the Nationwide insurance company.