Officers Kim Conte and Andy Krol took off Friday from Chicago. They returned Sunday after biking to Iowa, and back.
The cause behind the bike ride is personal to Conte, who lost her brother in 2017.
Conte's brother died from a heroin overdose.
Conte cycled 100 miles last year for the same effort.
The proceeds from this year's bike ride will go to The Heroin Epidemic Relief Organization, also known as HERO.