Not everything offered on a typical Chinese menu is authentically Chinese, but a presumption has grown that at least the major items of fare are. In the case of chop suey, this expectation may be misplaced.
Chop suey as served in the U.S. is a bland mixture of overcooked vegetables. (Which right there should tell you this dish probably isn't authentically Chinese — the Chinese would not dishonor honest vegetables so.) This popular menu item traditionally incorporates celery, onion, and thin noodles in a starchy sauce barely touched by soy sauce. Different regions add in other ingredients, with bean sprouts made part of the offering in one area, and sliced water chestnut and bamboo shoots another. Whatever is added, the underlying integrity of the dish is never compromised — chop suey must always be bland.
Its origins are as mysterious as the dish itself is guileless. According to a favored bit of lore, chop suey is a mispronounciation of "chopped sewage," an angered Chinese cook having mixed together the day's garbage in a bit of broth and presented it to San Francisco restaurant patrons who'd earned his ire. Not knowing any better, those being insulted loved the dish, and much to the amused bewilderment of their tormentors, returned time and again to order it.
Another account credits a resourceful cook who whipped up a dish of leftover meat and vegetables to placate a group of drunken miners. Yet another squares the responsibility on the shoulders of immigrant Chinese cooks charged with feeding laborers on the Pacific Railroad in California in the mid-1800s. When all the food they had to cook for dinner was an array of leftover odds and ends, they cooked it all together and called it chop suey. (Parents everywhere have learned this trick — when all else fails, throw everything that doesn't move too fast into one bowl, mix, heat, and christen it with an exotic name like "Indians on the War Path" or "Football Fiesta Surprise." Kids will then eat it, no matter what horrible thing it contains.)
Another "origin" claims a uniquely-mannered Chinese man was invited to the White House for dinner. That night's menu proved unpalatable to him, so he excused himself from the table and whipped up his own dish out of whatever he could find in the White House kitchen.
Some believe chop suey has a New York City origin, and go so far as to claim it was invented in 1896 by Chinese Ambassador Li Hung-Chang's chef. They say he devised this dish to appeal to both American and Oriental taste. Others claim the Ambassador often suffered acute indigestion after being plied with rich foods at obligatory banquets. His aide recommended a bland diet for the stricken Ambassador, and together they concocted chop suey.
The 1896 date is impossible, seeing the Oxford English Dictionary's first citation of "chop suey" comes from 1888, with said entry showing the term was even at that earlier date in widespread use:
A staple dish for the Chinese gourmand is chow chop svey [sic], a mixture of chickens' livers and gizzards, fungi, bamboo buds, pigs' tripe, and bean sprouts stewed with spices.
Possibly the dish came about because early Chinese miners and railway workers cooked together whatever vegetables and meats they had. In The Dictionary of American Food and Drink, John Mariani says the Mandarin words for chopped up odds and ends are "tsa sui," which is close enough to "chop suey" to support this theory. So is the OED's postulation of the Cantonese "shap sui" ("mixed bits") being anglicized into "chop suey." Indeed, the Cantonese origin theory is stronger, in light of most of the first Chinese immigrants being from the Canton area.
However, some sources argue for a Chinese origin for the dish, such as Li Shu-fan's 1964 Hong Kong Surgeon which describes chop suey as a local Toisanese dish (Toisan being a rural district south of Canton).
Although some sources posit a Cantonese dish as the true origin of chop suey, others note that what is called "chop suey" in the U.S. is virtually unknown in China and bears little resemblance to its supposed progenitor — so much so that, as Grace Zia Chu, cookbook author and teacher of Chinese cooking, wrote in The Pleasure of Chinese Cooking, when she was riding in Shanghai after World War II she spotted a neon sign that read: "Genuine American Chop Suey Served Here."