Big Blue Nation

The Big Blue Nation is the fan base of University of Kentucky (UK) athletics programs, particularly the men's basketball team, the women's basketball team and the football team. The Big Blue Nation is a reference to both the signature color of UK athletics (blue) and the fact that when the Wildcats play at a neutral site, the school's fans frequently make up a disproportionate majority of the crowd. For example, Yahoo! Sports columnist Pat Forde, a resident of Kentucky's largest city of Louisville, remarked after the 2014–15 men's basketball team finished its regular season undefeated,

The Southeastern Conference tournament is in nearby Nashville, and you can expect the seats to be 90 percent blue when the Cats play. Then they'll start the NCAA tournament in Louisville's home area, the Yum Center (sic), in a city where about 40 percent of the population roots for UK. The following weekend assuredly will be spent in Cleveland, a manageable drive from the Bluegrass State, and the Final Four is in Indianapolis, which is 114 miles up I-65 from the Ohio River that separates Kentucky and Indiana. You could put NCAA tourney sites in Kabul, Marrakesh and Reykjavík, and Kentucky would have the most fans in the gym. But when you make the commute this easy, the Big Blue occupation will be overwhelming.

...
Wikipedia