He was one of the first American trappers officially allowed into New Mexico, as part of the Glenn-Fowler Expedition of Hugh Glenn and Jacob Fowler.
Seeking food and water they cached their furs and went west to Baja California where they were arrested and imprisoned at San Diego from late 1828 to 1829.
By 1843, Slover had established himself and his family in California, settling near San Bernardino.
He continued to trap and hunt in the region, and died of injuries received in a bear attack in 1854.
[1] Issac Slover is also thought to be buried in the cemetery of Agua Mansa.