[1] The county was founded in May 1860 and named for Thomas Metcalfe, Governor of Kentucky from 1828 to 1832.

[2][3] Metcalfe County is part of the Glasgow, KY Micropolitan Statistical Area, which is also included in the Bowling Green-Glasgow, KY Combined Statistical Area.

25.20% of all households were made up of individuals, and 12.30% had someone living alone who was 65 years of age or older.

Metcalfe County lies at the northwestern end of the Unionist bloc of counties that covered the eastern Pennyroyal and the Pottsville Escarpment of the Eastern Coalfield.

Metcalfe itself was strongly Unionist during the Civil War,[13] and has been Republican for almost all the period since Reconstruction, though not to the same overwhelming extent as the counties to its east and south: Jimmy Carter even obtained 57 percent of the vote in 1976, and four other Democrats have narrowly carried the county since 1880 – although, as with all of rural Appalachia, the county has become overwhelmingly Republican in the twenty-first century due to views on environmental, social and cultural issues increasingly at odds with the national Democratic party.