What was Mariah Carey's first US No. 1 single?

American singer, songwriter, and actress Mariah Carey (born March 27, 1969) has released 86 official singles, 22 promotional singles, and has made 30 guest appearances. Her self-titled debut album in 1990 yielded four number-one singles on the Billboard Hot 100, the first being "Vision of Love", a song credited with revolutionizing the usage of distinguished vocal stylings, predominantly the practice of melisma, and effectively influencing virtually every female R&B performer since the 1990s.

"Vision of Love" was written by Carey and Ben Margulies. After being featured on Carey's demo tape for Columbia Records, the song was re-recorded and produced by Rhett Lawrence and Narada Michael Walden. The song features a slow-dance theme tempo and backing vocals sung by Carey herself, and introduces her usage of the whistle register. The lyrics of the song represent her past life filled with "alienation" and how she had dreamt of achieving her triumph over adversity up to the moment when it finally came to fruition as the "vision of love" that she had always believed in, despite everything that she had had to deal with.

Released on May 15, 1990, by Columbia Records, in the United States, "Vision of Love" entered the US 'Billboard' Hot 100 at number 73 during the week of June 2, 1990, and reached the chart's summit nine weeks later. The song remained atop the chart for four consecutive weeks, and was ranked sixth on the 'Billboard' Hot 100 year-end chart.