I administer a joint Y-DNA surname project that includes the name Hanrahan. We are interested in Hanrahan because in many genealogy records it can look like Hourihane (or vice versa), or sometimes Hourican (Hourican ->Hourigan). The three names - Hourihane, Hanrahan, and Horrigan - have three distinct genetic origins, according to our research so far.
If you are interested in expanding your family history research with genetic testing, can prove the origin of James Hanrahan to a more specific location in Co Clare (at least the civil parish), are willing to share your family history documentation, and you have a male Hanrahan relative willing to contribute a test sample, the project would be interested in funding a Y-DNA test kit of 37 markers for your Hanrahan relative.
The project has funded two kits so far for testers able to prove their ancestry back to a specific location in Ireland (townland or village, maybe the civil or church parish). I had to work with them a bit to "polish" the documentation and in both cases do some research to complete the missing link back to a specific location in Ireland, but we succeeded.
Please email me or message me if you are interested, and I'll point you to more information. There are (as of September 24, 2015) funds in place for one more kit.