Jefferson county is located in the north-central portion of the state, on the southernmost edge of the Appalachian Mountains. It is in the center of the (former) iron, coal, and limestone mining belt of the Southern United States.
Jefferson County is the most populous county in the state of Alabama. As of the 2010 census, its population was 658,466. Its county seat is Birmingham, which is the most populous city in the state.
The city of Kimberly developed around a stagecoach station built in the 1830s; it remained in service until 1865. At this time, the settlement was known as Kennelsville. The city then became known as Jefferson, probably after the nearby Old Jefferson coal mine, until the late 1880s. In 1888, the town’s post office was relocated to nearby Morris. In 1905, the town voted to change its name to Kimberly because another Alabama town had already claimed the name Jefferson