It covered an area larger than the states of Maryland, New Jersey, and Delaware combined.
Most present-day southern Idaho counties were created at least in part from the original Alturas County area.
"[1] Alturas County was created by the Idaho Territorial Legislature in February 1864.
Later that year the mining camp of Rocky Bar was designated the county seat.
On March 5, 1895, to circumvent a recent state supreme court decision striking down an earlier county reorganization, the Idaho Legislature combined Alturas and Logan Counties into a new county called Blaine.