Benjamin was born on April 5, 1775 in Beverly, Massachusetts.
His parents were Benjamin Ober and Mary Foster. He was the second child of four.
Benjamin married Sarah Gilham on December 11, 1794 in Wenham. They had twelve children, Rebecca (December 19, 1795 to September 13, 1796); William Foster (September 1, 1797 to June 27, 1798); Pamelia (May 15, 1799 to May, 1843); Sarah (March 23, 1802 to ?); Elizabeth (May 14, 1804 to 1810); Benjamin (August 12, 1806 to February 1836); Rebecca (October 30, 1808 to July 1, 1865); Peter Gilham (December 10, 1810 to ?); William (February 19, 1813 to November 3, 1869); Mary Elizabeth (January 29, 1815 to September 6, 1871); Ezekiel Francis (April 30, 1817 to ?), and Gustavus (October 27, 1819 to November 24, 1888).
Benjamin and Sarah migrated to Maryland after their marriage, but their last son was born in Beverly.
Benjamin died on October 1, 1836 at the age of 61 years, 5 months, 26 days. He is buried in Central Cemetery, Sub-Div. 10, Beverly, Massachusetts. The stone is broken and laying by the stones of his son and wife.