"Thank U, Next" by Ariana Grande
Ariana Grande's 2018 single "Thank U, Next" continued its Billboard Hot 100 reign into the first week of 2019. It had already been No. 1 for six weeks, and the seventh was its last on top of the chart.
"Sunflower" by Post Malone and Swae Lee
"Sunflower," a 2018 single from the soundtrack of "Spider-Man: Into the Spider-Verse," was No. 1 on the chart for the third week of 2019.
"7 Rings" by Ariana Grande
"7 Rings" reigned on the chart for eight nonconsecutive weeks. After debuting at No. 1, it remained in the top spot for five weeks. After two weeks at No. 2, it returned to No. 1 for three more weeks.
"Shallow" by Lady Gaga and Bradley Cooper
"Shallow," the lead single from the soundtrack of "A Star is Born," peaked at No. 1 for one week in March following its win for best original song at the 2019 Oscars.
"Sucker" by the Jonas Brothers
"Sucker" debuted at No. 1 on the Billboard Hot 100 and spent one week on top.
"Old Town Road" by Lil Nas X
After spending just five weeks on the chart, Lil Nas X's unlikely hit "Old Town Road" surged 15 spots on the Billboard Hot 100 for its first week at No. 1 in April.
"Old Town Road (Remix)" by Lil Nas X featuring Billy Ray Cyrus
After Lil Nas X added Billy Ray Cyrus to his remix of "Old Town Road," the new version displaced the original at No. 1. It went on to rule the chart for a record-breaking 19 weeks, the first song in history to do so.
"Bad Guy" by Billie Eilish
"Bad Guy" ended the historic reign of "Old Town Road" after spending nine weeks at No. 2 on the chart. It held the top spot for one week.
"Señorita" by Shawn Mendes and Camila Cabello
"Señorita" climbed to No. 1 for one week after spending some time at No. 2. It became Shawn Mendes' first No. 1 song and Camila Cabello's second.
"Truth Hurts" by Lizzo
"Truth Hurts" spent seven nonconsecutive weeks at No. 1 on the chart. It rose to the top spot in August, two years after its release, after Lizzo performed the song at the MTV Video Music Awards.
After six weeks at No. 1 and briefly losing the top spot, it reclaimed the title for one week.
"Lose You to Love Me" by Selena Gomez
"Lose You to Love Me" debuted at No. 15 on the Billboard Hot 100 after Selena Gomez released the ballad midweek, which is unusual for an artist that's looking for chart success. Following its first full week of data tracking, however, it surged to the top spot and became Gomez's first-ever No. 1 hit.
"All I Want For Christmas Is You" by Mariah Carey
Mariah Carey's timeless holiday ballad "All I Want for Christmas Is You" topped the chart for the first time since its release in 1994, becoming the singer's 19th No. 1 hit. It previously peaked at No. 3 in December 2018.
The song reached No. 1 the week before Christmas and remained there for the last full week of 2019.