From the 1885 History of Steuben County, Indiana  page 830

Robert Jackman, the first settler of Richland Township, Steuben Co., Ind., was born in Ireland in 1785.  When he was about five years of age his parents came to the United States and settled in Jefferson County, Ohio, where they spent the rest of their lives, and where he was reared and married in 1808 to Phebe Vail, a native of New Jersey.  Not long after their marriage they moved to Richland County, Ohio, and March 7, 1836, came to Steuben County and bought for himself and sons 640 acres of land in the southwestern part of the township, making his residence on section 30.  He was an energetic, enterprising man and made a fine farm of his land.  He was perfectly honorable and won many friends.  Coming as he did when the county was inhabited by Indians, he by his upright dealing with them won their confidence and had many friends among them.  He died in 1851 while on a visit to his old home in Richland County, aged 66 years.  His wife survived him many years and died at the home of her daughter, Mrs. Aldrich aged 82 years.  They had a family of twelve children, nine of whom grew to maturity;  all but one married and had families.  The sons are all dead.  Four of the five daughters are living -- all widows -- Mrs. Lydia Hill, of Montgomery County, Ohio;  Mrs. Margaret Johnson, of Richland Twp.;  Mrs. Mary A. Aldrich, of Otsego Twp., and Mrs. Jane Sanders.