There are no NFL teams in 26 states. This figure might rise depending on what defines a state as having an NFL club. The Jets and Giants are both based in New Jersey but name themselves New York. Nevada does not presently have an NFL franchise, but the Raiders will relocate to Las Vegas in 2020. The Redskins complicate matters. They are based in Washington, D.C., but can only play their home games in Landover because Maryland doesn't want them. This means that either Maryland or Virginia is required by law to let the Redskins play one game a season in their respective states.
New Jersey has a long-standing tradition of supporting football teams. The first pro team to call Newark home was now-defunct New York Football Club (NYFC), who played from 2015 to 2017 in the United States Soccer Federation (USSF)'s Major League Soccer (MLS). Before that, the Giants and Jets called Newark home for nearly 80 years each.
The Giants and Jets left New Jersey after the 1977 season and were replaced by the Buffalo Bills. The Bills played their first game at Roosevelt Stadium in Jersey City before moving to New York's Ralph Wilson Stadium in 1980. The Tampa Bay Buccaneers joined the NFL in 1966 and played their first two seasons in Tampa before moving to Sun Life Stadium in Miami in 1973. The Dolphins won the Super Bowl in 1968 and '75, so at least some New Jerseyan's are proud members of the NFL family.
The 32 NFL franchises are spread throughout 22 states. There are 28 states that do not have a football team. California, for example, has three teams: the Los Angeles Rams, the Los Angeles Chargers, and the San Francisco 49ers. Florida has two teams: the Miami Dolphins and the Tampa Bay Buccaneers.
In addition to these 30 teams, there is also a franchise in Toronto that is called the Toronto Argonauts. This makes the total number of NFL teams to be 32. The Argos play in the same city as the Buffalo Bills but they are a separate team from them. The Bills originally played in Boston before moving to Orchard Park, New York where they now reside. The Cleveland Browns also still exist in some form today. They were renamed the Baltimore Browns in 1999 after their move west but they still play their home games at Cleveland Stadium which is right across the street from where the original Browns played their games.
There have been attempts to establish other teams over the years but none have succeeded yet. There was one team in Houston that went by the name of Houston Oilers but they moved to Tennessee where they now play as the Titans. Another team named the Jacksonville Jaguars came into existence in 1994 when the Arizona Cardinals decided to move their team to Jacksonville. The new team was immediately successful and has gone on to win several more games than its predecessor ever did.
Although their name implies D.C., they play their games in Maryland (albeit Maryland already qualifies with the Ravens) and have their team facilities in Virginia. However, since Washington, D.C., is part of Maryland, the Redskins are considered out-of-state teams for licensing purposes.
The league's response? That licensing decision is left to its business managers, but given that the Redskins play in the same city as the Ravens, it seems likely that this is why the Raiders can use "Las Vegas" in promotional material without getting into legal trouble. A similar issue prevented the Carolina Panthers from using the word "Panthers" when they played at New York Giants facilities back in 2010. The NFL ruled that they could continue to use that term but not appear in television ads or print materials featuring players who were not actually on the field during that game.
In addition to the Raiders, other sports leagues have teams in Las Vegas. The NBA's Vegas Golden Knights will begin playing in the fall of 2017. And the MLB's Las Vegas 51s will begin play in April 2018.
The 51s are a minor league baseball team affiliated with the San Diego Padres. They will play their home games at Las Vegas Ballpark in Summerlin, about 15 miles west of the Strip.