Henry County was created by an act of the Legislature December 13, 1819 – one day earlier than Alabama became a state on December 14, 1819. Henry County was carved from Conecuh which had been a part of Monroe after it was formed from Washington County, the oldest county in the state, having been created by the proclamation of Governor Winthrop Sergeant of the Mississippi Territory on June 4, 1800. The area of Henry County on December 13, 1819 was vast in area. It embraced the present territory of Covington, Dale, Coffee, Geneva, Henry, Houston, parts of Pike, Crenshaw, Bullock and Barbour. The present area is 565 square miles. After the creation of Covington County from Henry, a part of Conecuh was left south of Henry which was later added to Henry County. Henry County was named for Patrick Henry, the Virginian known as the "Fireball of the Revolution", by the many first settlers from Virginia who came to this section.
The maps below display the boundaries of Henry County and the other counties as they were created. The white lines is the current boundary of each county with the red being the boundaries at various times since 1820.