There was once a heated rivalry between the Philadelphia Phillies and the Pittsburgh Pirates, as both teams are in the state of Pennsylvania and the cities of Philadelphia and Pittsburgh are approximately six hours apart by car on the Pennsylvania Turnpike.
From 1970 to 1980, both the Phillies and Pirates reigned exclusively as National League East Division champions, except in 1973, which was won by the New York Mets when they won the National League pennant. The Pirates won three straight, from 1970 to 1972 (During that time, they won the 1971 World Series), and again in 1974, and their championship season of 1979. From 1975 to 1978, the two teams finished first and second in the standings. The Pirates won the division in 1975, with the Phillies finishing right behind them and the Phillies won three straight division championships from 1976 to 1978. In each of those three years, the Pirates finished right behind them.
In the early 1990s, the Phillies and the Pirates reigned exclusively as division champions again from 1990–1993. The Pirates won three straight, from 1990–1992. During that time, the Phillies won the division in their pennant season of 1993. The Pirates won the 1991 championship at Three Rivers Stadium against the Phillies. Two years later, the Phillies division championship was won in Pittsburgh.
However, the rivalry came to an end of the 1993 season when MLB realigned for 1994 in the form of three divisions in each league, and the addition of an expanded playoff format. When agreeing on the realignment, the Pirates switched to the newly-created Central Division and gave up their spot in the NL East to the Braves.
Although the rivalry between the Phillies and Pirates doesn't exist, the Philadelphia–Pittsburgh rivalry is still evident in sports, as seen between the Philadelphia Flyers and Pittsburgh Penguins in the National Hockey League.