 The act creating Ada County in 1864 established the Ada County boundary common to Boise County as a line from Grimes Creek to Picket's Corral and then north from that point to the existing northern boundary of Boise County, leaving the areas outside of Emmett within Boise County.Jonathan Smith and Nathaniel Martin settled near Emmett about 1862.They established a ferry on the Payette River at Emmett in 1866.