Twubs.com is one of the official hashtag repositories.
While no hashtag can never be officially claimed, registering it via one of the register houses allows people to find out what the hashtag means.
If you were to do a search for #HCGOP, you might find Horry County GOP in SC. Now if someone looks us up they will find us as the “Official” registeree for #HCGOP.
Use #HCGOP in all your communications.