Wikipedia lists 126 total episodes of Parks and Recreation.
The series ran for seven seasons on NBC from April 9, 2009, through February 24, 2015. Its regular run contains 125 episodes, followed by A Parks and Recreation Special, which aired on April 30, 2020, and became the 126th episode overall.
The number can be confusing because some episode guides count only the original seven-season run and therefore show 125. Wikipedia includes the 2020 pandemic-era reunion special in the series total, producing the commonly cited figure of 126.
The show was created by Greg Daniels and Michael Schur and starred Amy Poehler as Leslie Knope. Episodes generally run about 22 minutes, although several specials and finales use longer formats. The final count therefore depends on whether the special is included, but Wikipedia's current series overview clearly gives 126.