To a large extent, the American Civil War was fought in cities and farms of Tennessee; only Virginia saw more battles. Tennessee was the last of the Southern states to declare secession from the Union, but saw more than its share of the devastation resulting from years of warring armies criss-crossing the state. Its rivers were key arteries to the Deep South, and, from the early days of the war, Union efforts focused on securing control of those transportation routes, as well as major roads and mountain passes such as the Cumberland Gap.