Vancouver Convention Centre as DoJ Courtroom
John Corben is being questioned during Lillian Luthor's trial when he attacks the courtroom using his Metallo abilities.
Source: What's Filming — Twitter
“Luthors” Filming Locations
Kara is the only person who believes Lena is innocent and must save her from Lillian.
Supergirl episode “Luthors” was filmed in Vancouver in Canada.
Oceanic Plaza as Outside the DoJ
Kara tries to stop Lillian and Metallo from fleeing but is forced to save a bunch of bystanders.
Vancouver Convention Centre as Lex Luthor's Lair
Lillian takes Lena to one of Lex's hidden lairs to retrieve some anti-alien weapons from an armory.
Source: What's Filming — Twitter