William Henry Allen was born 1850 Trumbull Co, OH was the youngest child of William T. Allen (1804 NY - bef 1860 OH) and Martha Maria ___ (1808 CT - bef 1880 Mahoning Co, OH).
William T. and Martha Marria married in NY before 1830 and had three children in Amsterdam, Montgomery Co, NY (Edwin died young, Prudence M. married Robinson Flick, & Pamelia who married Loren K. Wright) and two children born in Trumbull Co, OH (Russell S. and William Henry).
I have found this family in the following censuses: William T. Allen head: 1840 Lordstown, Trumbull Co, OH 1850 Bloomfield, Trumbull Co, OH*
Martha Maria Allen head: 1860 Canfield, Mahoning Co, OH* 1870 Ellsworth, Mahoning Co, OH*
William Henry Allen head: *appears in all of the starred census records above (couldn't find them in 1880 census, but all 3 of their 5 children who lived to adulthood were born in Indiana) 1900 Menomorie, Dunn Co, WI 1910 Menomorie, Dunn Co, WI 1920 Winter, Sawyer Co, WI 1930 Coureray, Sawyer Co, WI
I don't know about Jacob Clark raising them.It seems like they were raised by their own parents.