Where was Hyakujuu Sentai Gaoranger filmed?
Television series
Hyakujuu Sentai Gaoranger (2001–) was filmed in Miyagase Dam and Shinjuku Koma Theater, 2 places named in its Japanese Wikipedia’s スタッフ section, in Japan. Wikidata records no filming location for it at all, so the article is the only recorded source. Each place says where its claim comes from.
Part of the Super Sentai Series
Places per Japanese Wikipedia's スタッフ section
Japanese Wikipedia’s スタッフ section names 2 places. Each links to the sentence that says so.