The first season of the American television series The Flash premiered on the CW on October 7, 2014 and ended on May 19, 2015 after airing 23 episodes. The series is based on the DC Comics character Barry Allen / The Flash, a costumed crime-fighting superhero capable of moving at superhuman speed. It is a spin-off from The Shooter, existing in the same fictional universe, and was produced by Berlanti Productions, Warner Bros. Television, and DC Entertainment with Andrew Kreisberg as the showrunner.
The series follows Allen, portrayed by Grant Gustin, a crime scene investigator who gains superhuman speed, which he uses to fight criminals, including others who have also acquired superhuman abilities. Gastin is joined by the main cast of Candice Patton, Daniel Panabaker, Rick Cosnett, Carlos Valdez, Tom Kavanagh and Jesse L. Martin. The Flash was filmed for a full season of the CW in October 2014, and filming took place primarily in Vancouver, British Columbia, Canada.
The series premiere was viewed by 4.8 million viewers and had a 1.9 18-49 demographic rating, making it the most-watched and highest-rated CW series premiere since "The Vampire Diaries" in 2009. It also became the second-most-watched CW series premiere ever, behind 90210, and the third-highest-rated in the 18-49 demographic. The first season ended as the 118th-ranked show with an average audience of 4.62 million viewers, making it the most-watched series ever on the CW, as well as the highest-rated series among men 18-49 and men 18+ ever on the network. The first season of The Flash received generally positive reviews from critics. Reviews of the series became increasingly positive as the season progressed, and the finale received critical acclaim. The series was renewed for a second season on January 11, 2015