While we once had an article on the O'Higgins clan, it didn't cite reliable sources backing up the information, such as textbooks on Irish history or articles in reputable magazines. In fact, it gave no indication that the various O'Higginses actually all belonged to the same clan. Thus what could be used of it was merged into the article on the family. 
You can use the Article Wizard to write a new draft that summarizes what such sources report about the clan. Please note that we also have an article entitled Ó hUiginn, though that too is in dire need of work - right now it basically duplicates O'Higgins (surname).