[2] Cassia County is included in the Burley, ID Micropolitan Statistical Area.

It was trappers who initially developed the Oregon Trail, which ran on the county's northern border.

A stage line through the county was established between Kelton, Utah and Boise, Idaho in 1869.

Other elected officials include clerk, treasurer, sheriff, assessor, coroner, and prosecutor.

At the state level, Cassia County is in Legislative District 27, represented by Senator Kelly Anthon of Declo, Douglas Pickett of Oakley and Clay Handy of Burley.

[9] In the presidential election of 2012, Mitt Romney, whose father lived for a few years in his youth in Oakley, carried Cassia County with 85.2% while Barack Obama received 13.1%.

[10] The last Democratic presidential candidate to carry Cassia County was Franklin Roosevelt in the election of 1940 edging out Wendell Willkie by around 100 votes.

State legislators from Cassia County traditionally hold their seats for long periods of time.

The only other member of congress with ties to the county is Henry Dworshak who represented Idaho's 2nd congressional district and later served in the Senate.

The northern half of the county is part of the Magic Valley region of the Snake River Plain, and numerous mountain ranges extend north from the southern boundary and diminish as they approach the river, which flows from east to west.

The Silent City of Rocks National Reserve, containing exposed granitic batholith as old as 2.5 billion years, is located in the southern part of the county.

As of the 2010 United States Census, there were 22,952 people, 7,666 households, and 5,758 families living in the county.

[citation needed] Other portions are in:[23] The county is in the catchment area, but not the taxation zone, for College of Southern Idaho.