According to an interview with Veronica Cartwright, she left the series because the producers wanted to have her character of Jemima Boone involved in more mature situations, such as budding romantic relationships. Patricia Blair did not like this because it made her feel too old, so she threatened to leave the series if Cartwright was not let go from the series.
Israel Boone would be one of 72 killed at the Battle of Blue Licks, one of the last battles of the Revolutionary War, on 19 Aug 1782. He was 23. His father, Daniel, was there and saw his son killed. Coincidentally, Darby Hinton, who played Israel, was born on the 175th anniversary of Israel's death, 19 Aug 1957.
Israel Boone is portrayed as being the third child, with two older sister, Jemima being older than Israel. Actually, the Boone's had ten children as follows: James Boone (1757-1773), Israel Boone (1759-1782), Susannah Boone (1760-1800), Jemima Boone (1762-1834), Levina Boone (1766-1802), Rebecca Boone (1768-1805), Daniel Morgan Boone (1769-1839), Jesse Bryan Boone (1773-1820), William Boone (1775-1775), and Nathan Boone (1781-2856).