Team Logo. The Gateway Grizzlies are a team in the Frontier League. They won the league championship in 2003. They are one of the longest tenured teams in the league. Retrieved from "https://prosportsteams.fandom.com/wiki/Gateway_Grizzlies?oldid=12012" Categories: Frontier League Teams Teams in Illinois Add category Cancel Save Community content is available under CC-BY-SA unless otherwise noted.