The Grand Divisions are three geographic regions in the U.S. state of Tennessee, each constituting roughly one-third of the state's land area, that are geographically, culturally, legally, and economically distinct. The Grand Divisions are legally recognized in the state constitution and state law and are represented on the Flag of Tennessee by the flag's three prominent stars. The Grand Divisions, East, Middle, and West Tennessee, are sometimes referred to as "three states of Tennessee" or "the three Tennessees". Definitions The three Grand Divisions, East, Middle, and West Tennessee, are formally defined in state law at Tennessee Code Annotated Title 4, Chapter 1, Part 2 ("Grand Divisions and State Capital") as the "eastern, middle, and western" Grand Divisions of the state. The law lists the counties in each region. The boundary between East Tennessee and Middle Tennessee is on the Cumberland Plateau, which was a major barrier to travel and commerce during much of the state's early history. The boundary is close to the line between the Eastern and Central time zones. All but three counties of East Tennessee (Bledsoe, Cumberland, and Marion) are in the Eastern Time Zone, while Middle and West Tennessee are entirely in the Central Time Zone. The reach of the Tennessee River that flows northward to Kentucky from Mississippi and Alabama demarcates the boundary between Middle and West Tennessee starting from the northern border of Hardin County, which is split down the middle by the Tennessee River but is located wholly in West Tennessee. The assignments of counties can be changed by the state legislature, but few changes to the boundaries between the Grand Divisions have been made since the earliest legal reference to them, in The Acts of Tennessee 1835-1836, Chapter 3, "An Act to establish a Supreme Court in pursuance of the 2nd sec., art. 6, of the Constitution of the United States". The most recent adjustment to the boundaries of the Grand Divisions occurred in 1965, when Perry County was shifted from West Tennessee to Middle Tennessee. Earlier in the 20th century, there were definitional changes that shifted the assignments of Marion, Sequatchie, and Cumberland Counties between East and Middle Tennessee (Sequatchie moved from East to Middle Tennessee; Marion and Cumberland counties moved from Middle to East Tennessee). Statistics Characteristics The three regions are geographically and culturally distinct. East Tennessee's landscape is dominated by the Appalachian mountain chain, including the Great Smoky Mountains