By any chance is this your family? I too have the Keenan Surname who came from Fermanagh, Ireland and went to Philadelphia, Pennsylvania. I found the surname Keenan in the census under various spellings.
Name: Barbara Kenann Age in 1860: 46 Birth Year: abt 1814 Birthplace: Pennsylvania Home in 1860: Derry, Westmoreland, Pennsylvania Gender: Female Post Office: Livermore
Household Members: Name Age John Kenann 49 Barbara Kenann 46 Levi Kenann 18 Terrissa Kenann 17 Andrew Kenann 15 Rebecca Kenann 11 Mary Kenann 9 Joseph Kenann 7 Barbara Kenann 4 Richard Kenann 1