5. Ramapo Fault
Length: 185 miles
Next in line on our list of biggest fault lines in US is Ramapo Fault that came to prominence in the 1970s, when it was discovered that it runs beneath the Indian Point nuclear power plant. It is easy to see why it is considered very dangerous when you add the fact that most of Ramapo Fault lie under New Jersey, the most densely populated state in the US.
