The Texas Hill Country is a geographic region of Central and South Texas, forming the southeast part of the Edwards Plateau. Given its location, climate, terrain, and vegetation, the Hill Country can be considered the border between the American Southeast and Southwest. The region represents the very remote rural countryside of Central Texas, but also is home to growing suburban neighborhoods and affluent retirement communities. The region is notable for its karst topography and tall rugged hills of limestone or granite. Many of the hills rise to a height of above the surrounding plains and valleys, with Packsaddle Mountain rising to a height of above the Llano River in Kingsland. The Hill Country also includes the Llano Uplift and the second-largest granite dome in the United States, Enchanted Rock. The terrain throughout the region is characterized by a thin layer of topsoil and many exposed rocks and boulders, making the region very dry and prone to flash flooding. Native vegetation in the region includes various yucca, prickly pear cactus, desert spoon, and wildflowers in the Llano Uplift. The predominant trees in the region are Ashe juniper and Texas live oak. Bound on the east by the Balcones Escarpment, the Hill Country reaches into the far northern portions of San Antonio and western portions of Travis County including the cities of Austin and Lago Vista. As a result of springs discharging water stored in the Edwards Aquifer, several cities such as Austin, San Marcos, and New Braunfels were settled at the base of the Balcones Escarpment. , the region's economy was one of the fastest growing in the United States. According to the Texas Parks and Wildlife Department, these 25 counties are included in the Hill Country Wildlife District: Bandera Bell Blanco Burnet Comal Coryell Crockett Edwards Gillespie Hays Kendall Kerr Kimble Lampasas Llano Mason McCulloch Menard Real San Saba Schleicher Sutton Travis Val Verde Williamson During the American Civil War, due to its large, pro-Union, German immigrant population, the Texas Hill Country was opposed to Texas seceding from the Union.