Yes, it is possible to trademark a hashtag. A hashtag is a word or phrase preceded by a hash symbol (#) that is used to identify a particular topic or theme on social media platforms. Hashtags are often used to organize and categorize content and to facilitate searches on social media.
As trademark rights in the United States are based on use, you will need to demonstrate that you are using the hashtag as a trademark to identify your products or services. This means that you must be using the hashtag to identify the source of your products or services and not just as a general term to describe your products or services.
Beyond that, the process of trademarking a hashtag is no different than trademarking any other word or slogan. You will need to file a trademark application with the appropriate trademark office, and provide information about your use of the hashtag as a trademark, as well as any other relevant information about your products or services.