The numerical designation for Lewis and Clark County (used in the issuance of the state's license plates) is 5.

[3][4] Lewis and Clark County is part of the Helena, Montana Micropolitan Statistical Area.

Lewis and Clark County leans slightly Republican, but it has voted for Democratic candidates three times since 1964.

Barack Obama carried the county in 2008 but lost it to Mitt Romney in 2012.

In recent elections, the county has voted Republican but only by narrow margins.