Mailia Aguigui hit three 3-pointers and finished with 12 points as the Titans improved to 4-0 on the season with a non-league win.
After holding the Chieftains to one point in the first quarter, Union took a 17-9 lead into halftime before opening up a 35-17 lead after three quarters.
Sarah Trostle added five points and six rebounds, and McKenzie English also had six rebounds for the Titans.
Teaghan Cowles led Columbia River with eight points.
UNION 46, COLUMBIA RIVER 24
COLUMBIA RIVER (1-2) — Ellie Furth 3, Maddy Kessi 1, Kate Kraft 0, Teaghan Cowles 8, Gabrielle Collins 5, Katie Kolbe 4, Anna Klundt 2, Yaiydenn Lopez-Perez 0, Emma Fisk 1. Totals 8 (3) 5-11 24.