The 2005 Seattle Seahawks season was the franchise's 30th season in the National Football League (NFL), their fourth playing their home games at Qwest Field and their seventh season under head coach Mike Holmgren. They won the National Football Conference (NFC) Championship Game and played in Super Bowl XL, which they lost 21–10 to the Pittsburgh Steelers. The Seahawks compiled a 13–3 record in the regular season, easily winning the NFC West and earning the NFC top seed, thus clinching home field advantage in the NFC playoffs for the first time in franchise history. There, they beat the Washington Redskins and Carolina Panthers to win the George Halas Trophy, and advance to their first ever Super Bowl. Combining the regular season and postseason, the Seahawks finished with a perfect 10–0 record at Qwest Field. The 2005 team was widely considered the best team in club history until the Super Bowl XLVIII championship. The 2005 season was also the team's 30th anniversary season in the NFL. The Seahawks were the only NFC team from the 2004 playoffs to qualify for the 2005 playoffs.

Lumen Field is a multi-purpose stadium in Seattle, Washington, United States. Located in the city's SoDo neighborhood, it is the home field for the Seattle Seahawks of the National Football League (NFL), Seattle Sounders FC of Major League Soccer (MLS), and Seattle Reign FC of the National Women's Soccer League (NWSL). Originally called Seahawks Stadium, it was renamed Qwest Field in June 2004 when telecommunications carrier Qwest acquired the naming rights. The stadium became known as CenturyLink Field following Qwest's June 2011 acquisition by CenturyLink and was nicknamed "The Clink" as a result; it received its current name in November 2020 with CenturyLink's rebrand to Lumen Technologies. It is a modern facility with views of the Downtown Seattle skyline and a seating capacity of 68,740 spectators for NFL games and 37,722 for most MLS matches. The complex also includes the Event Center which is home to the Washington Music Theater, a parking garage, and a public plaza. The venue hosts concerts, trade shows, and consumer shows along with sporting events. Located within a mile (1.6 km) of Downtown Seattle, the stadium is accessible by multiple freeways and forms of mass transit.