Dirty River Derby

The Dirty River Derby, also known as the River Cities Cup, is a rivalry between American soccer clubs representing Cincinnati, Ohio and Louisville, Kentucky. From 2016 to 2018, the cities were respectively represented in the second-tier league now known as the USL Championship by FC Cincinnati and Louisville City FC. Both teams played in the Eastern Conference of what was then known as the United Soccer League, and the River Cities Cup was contested solely in regular-season matches between the two sides, with the winner of the regular-season series claiming the cup. After the 2018 season, FC Cincinnati ceased USL operations, with the ownership group having been awarded a Major League Soccer franchise that began play under the FC Cincinnati name in 2019. From that point forward, the rivalry only takes place if the two teams are drawn together in the U.S. Open Cup, with the first such meeting after FC Cincinnati's arrival in MLS taking place in 2019.

The teams are located in cities situated on the Ohio River and are separated by roughly 100 miles of Interstate 71. The winner of the regular-season series won the cup for that year.

The last regular-season league match between the teams began on September 11, 2018 (resumed and completed on September 14 due to weather), with FC Cincinnati winning 1–0. The final cup holders are Louisville City, who retained the cup by winning the previous two regular-season matches that season.

Before the formation of Louisville City and FC Cincinnati, various soccer clubs, both professional and amateur, played in the respective regions. The Derby City Rovers played in the fourth-division Premier Development League and played at the Woehrle Sports Complex in Louisville's northern suburb, Jeffersonville, Indiana. The Louisville metropolitan area also housed two indoor soccer teams prior to Louisville City: the Louisville Lightning, who played in the Major Arena Soccer League from 2009 until 2013, and the Louisville Thunder who played in the American Indoor Soccer Association from 1984 until 1987.

The rivalry between the two cities long predates the arrival of professional soccer in the region; most notably, the largest universities in the two cities, the University of Cincinnati and University of Louisville, had a longstanding football rivalry that ended in 2013 due to conference realignment.

Both clubs were formed in the early to mid 2010s. The formation of Louisville City FC began with the formation of the club's current supporters group, The Coopers, whom aimed to build a grassroots support base to bring a professional soccer team to Louisville. The following year, a local ownership group invited the owners of Orlando City to meet with the Coopers supporters group. In 2015, the team Louisville City was born and served as the USL affiliate for Orlando City as they jumped from USL to Major League Soccer. In 2016, the affiliation ended with Orlando City creating its own reserve team to field in USL.

That same year, reports swirled of USL seeking expansion into Cincinnati. The formation of the ownership group came from a partnership between the Cincinnati Bengals NFL franchise and the former soccer club in the region, the Cincinnati Kings, when Jeff Berding was named as part of the potential ownership group. In the summer of 2015, more details on the new club were announced. The Lindner family, of American Financial Group headquartered in Cincinnati, was announced the owner of the new club with Carl Lindner III representing the owners at the press conference. Subsequently, the team name "FC Cincinnati" was announced as the club's name, as well as their coach, and stadium.

While already unofficially known among fans as "The Dirty River Derby", an online poll by both clubs was released asking fans what their preferred name for the series cup would be. Amongst the options included the "River Cities Cup", the "Steamboat Cup", the "Royal Cup", the "100 Mile Cup" or the "Riverboat Rivalry Cup". On February 5, 2016, it was announced the "River Cities Cup" had won.