Heart of Illinois Big Brothers Big Sisters operates under the belief that inherent in every child is incredible potential. As the nation’s largest donor- and volunteer-supported mentoring network, Heart of Illinois Big Brothers Big Sisters makes meaningful, monitored matches between adult volunteers (“Bigs”) and children (“Littles”), ages 5 through 18 in Peoria, Tazewell, Woodford, Fulton, and Knox counties. We develop positive relationships that have a direct and lasting effect on the lives of young people.