 Due to the relative precision of the survey of 36°30′ on the Mississippi River, Congress decided to continue the line west as the northern boundary of Arkansas Territory, with the exception of the Missouri Bootheel.The parallel 36°30′ north is part of a nearly straight east-west line of state borders (with small variations) starting on the East Coast of the United States, beginning with the border between Virginia and North Carolina.However, this boundary and the one between Kentucky and Tennessee line lies a few miles north of 36°30′ in places.