IPAs began when the British started aggressively hopping beer to send to their soldiers in India, as hops are a preservative as well as a flavoring agent.
American India Pale Ale
American hops such as Cascade, Centennial, Citra, Tomahawk, Warrior, etc. import resiny, piney, floral, and/or citrusy notes that are more pronounced than the original IPAs from England.
Session India Pale Ale