Halloween in the United States is the season for all things scary – particularly haunted houses. Most areas have a local haunted house, but for those looking for an extra terrifying thrill, there are many elaborate haunted houses throughout the country. Here are 5 of the best haunted houses in the United States. Terror Behind the Walls. Terror Behind the Walls is an annual haunted house that takes place at the Eastern State Penitentiary located in Philadelphia, Pennsylvania. Can you picture that? The setting itself is enough to terrify me. The Eastern State Penitentiary is one of the most infamous prisons in the US, due to its size. Terror Behind…