What song was number 1 for the most weeks?

The song that has held the record for the most weeks at number one on the Billboard Hot 100 chart in the United States is "Old Town Road" by Lil Nas X featuring Billy Ray Cyrus. The song spent a total of 19 weeks at the top of the chart in 2019, breaking the previous record held by "One Sweet Day" by Mariah Carey and Boyz II Men, which had spent 16 weeks at number one in 1995.