Lyons Township Assessor Pat Hynes and County Board President Toni Preckwinkle won the Democratic nominations Tuesday in their respective primary races. 

Just one of two top incumbents prevailed in competitive Cook County Democratic Party primary elections Tuesday night. Board President Toni Preckwinkle secured a fifth term as county executive, but Assessor Fritz Kaegi failed to secure a third term, falling behind a challenger who had the backing of the county party.