Ala. Code § 41-2-1: General Description.

The boundaries of this state are established and declared to be as follows: Beginning at the point where the thirty-first degree of north latitude crosses the Perdido River; thence east to the western boundary line of the State of Georgia; thence along said line, to the southern boundary line of the State of Tennessee; thence west along the southern boundary line of the State of Tennessee, crossing the Tennessee River, and on to the second intersection of said river by said line; thence up said river to the mouth of Big Bear Creek; thence by a direct line to the northwest corner of Washington County, in this state, as originally formed; thence southerly along the line of the State of Mississippi to the Gulf of Mexico; thence eastwardly, including all islands within six leagues of the shore, to the Perdido River; and thence up the said river to the beginning.