What NFL team is in the smallest city?

The most commonly accepted definition of a "major" professional league is the "Big Four." The "Big Four" includes the top four professional sports organizations; the National Football League (NFL), Major League Baseball (MLB), the National Basketball Association (NBA), and the National Hockey League (NHL).

NFL news:

Among all 32 NFL teams, the Green Bay Packers are based in the smallest U.S. market, ranking 139th in the country. In comparison, the city of New Orleans ranks a spot above Green Bay for 31st in population, having the 51st highest population in the country. Jacksonville joins Green Bay as the only city to have an NFL-exclusive team among the "big four" sports leagues.

Green Bay, Wisconsin, is the smallest market to have a major pro sports team because of a population of around 105,100. Many early NFL franchises were in small cities (like the Chicago Bears, who started in Decatur, Illinois, as the Decatur Stanleys). The Packers have somehow managed to stay in Green Bay for almost a century (without moving to Milwaukee).

Green Bay may be the smallest city or metropolitan area but not the most miniature fan base. And while they certainly are not the wealthiest franchise, they are lucrative franchise. Without a deep-pocketed owner, they have fought hard and made pragmatic moves to build and preserve fan loyalty (including consistent winning, to say the least) to become a gemstone of a franchise.

Notwithstanding the small market of Green Bay, The Packers are uncommonly famous all over Wisconsin. In Milwaukee (despite being over 120 miles away from Green Bay), the Packers are more popular than the sports teams that actually play in Milwaukee. The people there are as die-hard Cheeseheads, a slur used by the Bears fans to insult the Packers fans.

In fact, the Packers don't belong to the residents of the Green Bay area, they belong to the entire state of Wisconsin.