I'm investigating the Gallaher / Gallagher's of Butler County, Pennsylvania; particularly those in the Muddy Creek and Franklin townships.

In the 1850 census for Franklin Township, there is a Charles Gallaher, age 89, b. Ireland, living with wife Catharine, age 82, b. Ireland.

In the same household are a Wm. Gallaher, age 31, a Margaret Gallaher, age 26, and a Catherine Double, age 10.

Is anyone familiar with these individuals?

The age gap between Wm and Catharine Gallaher is significant, so I'm assuming he's not a child of Charles and Catharine. Is he a grandson? Who were his parents?

Is Margaret the wife or sister of Wm?

Who is Catharine Double and why is she living in this household? Granddaughter of the elder Catharine? Great granddaughter? Are her parents deceased?

Any help appreciated!