Keystone or key-stone or variation, may refer to: Keystone (architecture), a central stone or other piece at the apex of an arch or vault Keystone (cask), a fitting used in ale casks Business Keystone Law, a full-service law firm Digital Keystone, a developer of digital entertainment software Keystone Aircraft Corporation Keystone Bridge Company, an American bridge building company Keystone (beer brand) Keystone Camera Company Keystone (gasoline automobile) Keystone (steam automobile) Keystone Pipeline, a crude oil pipeline Keystone-SDA/Keystone-ATS, a Swiss press agency Keystone View Company, a US photo agency Keystone (Berkeley, California), a defunct music club Entertainment Keystone (video game), part of the Xbox Live Arcade title Fable 2 Pub Games Keystone (band), led by jazz trumpeter Dave Douglas Keystone (album), a 2005 album by the band Keystone Cops, a silent movie series Keystone Kapers, a classic Atari game Keystone Studios, a movie studio Places The Keystone asterism in the Hercules constellation United States The "Keystone State", nickname for the U.S. Commonwealth of Pennsylvania Keystone, Colorado, a town Keystone Resort, the related ski resort Keystone, Florida, an unincorporated community Keystone, Indiana Keystone, Iowa Keystone, Nebraska Keystone, North Dakota Keystone, Ohio Keystone, South Dakota, a town near Mount Rushmore Keystone, Wyoming Keystone at the Crossing, a business/shopping district in Indianapolis, Indiana The Fashion Mall at Keystone, located in the Keystone shopping district Keystone Heights, Florida Keystone Canyon, Alaska Keystone Lake, a resort area near Tulsa, Oklahoma Keystone, Wisconsin Canada The "Keystone Province", a nickname for the Province of Manitoba Keystone Centre, an arena and exhibition centre in Brandon, Manitoba Fictional locations Keystone City, home of the comic book character The Flash Keystone City, a holographic city in the Star Trek: The Next Generation episode "Emergence" Railroads Keystone Corridor, a rail corridor from Philadelphia to Pittsburgh Keystone Service, a current New York-Harrisburg service Keystone (Amtrak train, 1979-1981), a predecessor of the current service Keystone (Amtrak train, 1971-1972), a former New York-Pittsburgh service operated by Amtrak Keystone, a former New York-Washington service operated by the Pennsylvania Railroad Keystone (train), a lightweight train used for the service Schools Keystone School, a private K-12 school in San Antonio, Texas, USA Keystone National High School, a private correspondence school Keystone Exam, a Pennsylvania standardized test Sports Keystone Junior Hockey League, in Manitoba Keystone Cup, Western Canadian Junior "B" ice hockey championship Keystone (horse), a racehorse Other uses Keystone (limestone), quarried in the Florida Keys Keystone effect, caused