Nowhere in China. American Chinese cuisine (and its relatives in Australia, Europe, etc) is heavily adapted for Western tastes:

"Chinese-American cuisine is 'dumbed-down' Chinese food. It’s adapted... to be blander, thicker and sweeter for the American public"

Some dishes are localized versions of actual Chinese dishes (eg. Kung Pao chicken, which completely lacks the málà kick of the Sichuanese original), many were created in America (fortune cookies, "Mongolian beef", etc). The Wikipedia article above has a good list of both.

Also, I've eaten a lot of "real" Fujianese (Hokkien) food in Singapore, where they're the single largest dialect group, and I can assure you that neither Fujian nor Hakka cuisine bears the slightest resemblance to Panda Express.

Incidentally, this phenomenon is by no means unique. For example, Indian Chinese is what happens when Chinese and Indian cuisines collided, in Japan you can try out heavily Japanized Western dishes (yōshoku) like "omelette rice", and everybody has bastardized the poor Italians. Of course, things get really interesting when these get re-exported back to the home country, which is why you can now find American Chinese food in Shanghai!

Nowhere in China. American Chinese cuisine (and its relatives in Australia, Europe, etc) is heavily adapted for Western tastes:

"Chinese-American cuisine is 'dumbed-down' Chinese food. It’s adapted... to be blander, thicker and sweeter for the American public"

Some dishes are localized versions of actual Chinese dishes (eg. Kung Pao chicken, which completely lacks the málà kick of the Sichuanese original), many were created in America (fortune cookies, "Mongolian beef", etc). The Wikipedia article above has a good list of both.

Also, I've eaten a lot of "real" Fujianese (Hokkien) food in Singapore, where they're the single largest dialect group, and I can assure you that neither Fujian nor Hakka cuisine bears the slightest resemblance to Panda Express.

Incidentally, this phenomenon is by no means unique. For example, Indian Chinese is what happens when Chinese and Indian cuisines collide, in Japan you can try out heavily Japanized Western dishes (yōshoku) like "omelette rice", and everybody has bastardized the poor Italians. Of course, things get really interesting when these get re-exported back to the home country, which is why you can now find American Chinese food in Shanghai!