The Houston Astros are an American professional baseball team based in Houston, Texas. The Astros compete in Major League Baseball (MLB) as a member club of the American League (AL) West division, having moved to the division in 2013 after spending their first 51 seasons in the National League (NL).
The Astros have completed 56 seasons in Major League Baseball, qualifying for the postseason eleven times and reaching the World Series twice (2005 and 2017). Established as an expansion franchise in 1962, the team's first winning season was in 1972.
In 2014, Sports Illustrated predicted the Astros would win the 2017 World Series through their strategic rebuilding process. As of June 9, the Astros were 41–16, which gave them a 13.5-game lead over the rest of their division, and they had comfortable possession of the best record in the entire league. This was the best start in the Astros' 55-year history. As the games of June 23 concluded, the Astros had an 11.5-game lead over the rest of the division. The Astros entered the All-Star Break with an American League-best 60–29 record and a 16-game lead in the division, although the overall best record in MLB had just barely slipped to the Dodgers shortly before the All-Star Break by just one game.
The Astros clinched their first division title as a member of the American League West division, and first division title overall since 2001. They also became the first team in Major League history to win three different divisions: National League West in 1980 and 1986, National League Central from 1997 to 1999 and 2001, and American League West in 2017. On September 29, the Astros won their 100th game of the season, the second time the Astros finished a season with over 100 wins, the first being in 1998. They finished 101–61, with a 21-game lead in the division, and faced the Red Sox in the first round of the AL playoffs. The Astros defeated the Red Sox three games to one, and advanced to the American League Championship Series against the New York Yankees. The Astros won the ALCS four games to three, and advanced to the World Series to play against the Los Angeles Dodgers. The Astros defeated the Dodgers in the deciding seventh game of the World Series, winning the first championship in franchise history.