University Drive (between 105a & 107a) as Runaway School Bus
Kara stops an out of control schoolbus and is then sees Lena who punches her all in Lena's simulation.
“Event Horizon” Filming Locations
Kara is attempting to work up the courage to tell Lena her secret when she learns that Lena sold CatCo while a mysterious shapeshifter summons one of J'onn's enemies from the Phantom Zone.
Supergirl episode “Event Horizon” was filmed in Surrey & Vancouver in Canada.
Prado Cafe as Noonan's
Kelly tells Kara, Alex, and J'onn about her new job over coffee and after she leaves Alex tries to convince Kara to come clean to Lena.
Orpheum Theatre Vancouver as Theater
Kara finally comes clean to Lena just before Lena introduces her at the awards ceremony which is soon interrupted by Midnight.
Source: What's Filming