Ontario Heartland Chorus was founded from an amalgamation of the Mississauga City Chorus and the Trillium Oakville Chorus on February 8, 1996, chartered with Sweet Adelines International. Under the co-direction of Anne Prins and Fred Lilly, Ontario Heartland's first competition was in the spring of 1996 in Syracuse, NY.

Directed by Anne Prins from 1997 to 2012, Ontario Heartland Chorus earned several Regional medals, including First Place and Second Place medals in the small chorus division. 

Jan-Ake Westin became Director in 2013, taking the chorus to First Place and Second Place (small chorus), and earned Most-Improved Chorus Award in 2016.

Hannah Barton joined as Co-Director in 2018 and, under their co-directors, Ontario Heartland broke through into the top five for the first time, earning a fourth-place overall finish.

Hannah took the chorus forward as sole director in 2019 when Ontario Heartland Chorus again placed fourth overall and won the small chorus division.

The year 2019 welcomed two changes: Leila Brown joined as Assistant Director in June; and the chorus name was changed to The Heartland Singers in November.

COVID-19 restrictions prevented regional competitions from taking place in 2020 and 2021.