Nebraska is almost one of those blanket states, which look like a blanket on a map, as they are bordered by latitudes and longitudes. The northern and southern borders are latitudes. The western border is almost straight, but Colorado bites a corner off. The main exception, chaos in the world of order, is the eastern border, formed by the Missouri River. The border meanders through the map like a Mandelbrot picture.
The state is a central prairie state, little relief and thus little possibilities for karstification. According to the Gurnee Guide there are no show caves in this state.