where was the last episode of the oc mainly filmed at?

Answer 1

Not sure about the exact location for the final episode, but here's a list of all the filming locations according to imdb.com:

Filming locations for
"The O.C." (2003)

Hermosa Beach, California, USA

Malibu, California, USA
(Newport Beach exteriors)

Manhattan Beach, California, USA

Mira Costa High School - 701 S. Peck Ave., Manhattan Beach, California, USA

Mount St. Mary's College, Los Angeles, California, USA
(Harbor High School)

Ocean Trails Golf Club, Rancho Palos Verdes, California, USA

Raleigh Studios - 1600 Rosecrans Avenue, Manhattan Beach, California, USA
(Studio)

Rancho Palos Verdes, California, USA
(Newport Beach exteriors)

Redondo Beach, California, USA

Torrance, California, USA

Wayfarer's Chapel - 5755 Palos Verdes Drive South, Rancho Palos Verdes, California, USA
(OC wedding and funeral)

Answer 2

There's a huge list of The OC filming locations at http://www.seeing-stars.com/OC

Answer 3

Oh piss! I was about to suggest the T4 on Channel Four will be showing it on Sunday - and then I realised it was on Sunday past and I missed it too! Waaaah! D. X