It seems that the Yellow Kid wasn´t the first comic ever published in U.S. :D

Proto-comic books and the Platinum Age

The development of the modern American comic book happened in stages. Publishers had collected comic strips in hardcover book form as early as 1833, with The Adventures of Obadiah Oldbuck, which appeared in New York in 1842, as the first example published in English.The G. W. Dillingham Company published the first known proto-comic-book magazine in the U.S., The Yellow Kid in McFadden's Flats, in 1897. It reprinted material – primarily the October 18, 1896 to January 10, 1897 sequence titled "McFadden's Row of Flats" – from cartoonist Richard F. Outcault's newspaper  comic strip Hogan's Alley, starring a character called the Yellow Kid. The 196-page, square-bound, black-and-white publication, which also includes introductory text by E. W. Townsend, measured 5x7 inches and sold for 50 cents. The neologism "comic book" appears on the back cover. 

Despite the publication of a series of related Hearst comics soon afterward (including the first known full-color comic, The Blackberries, in 1901) the first monthly comic book (Comics Monthly) did not appear until 1922 and only lasted a year.The Funnies and Funnies on Parade.

In 1929 Dell Publishing (founded by George T. Delacorte Jr.) published The Funnies, described by the Library of Congress as "a short-lived newspaper tabloid insert". (Do not confuse this with Dell's later comic book of the same name, which began publication in 1936.) Historian Ron Goulart describes the 16-page, four-color periodical "more a Sunday comic section without the rest of the newspaper than a true comic book. But it did offer all original material and was sold on newsstands". It ran 36 issues, published Saturdays through Oct. 16, 1930.

In 1933, salesperson Maxwell Gaines, sales manager Harry I. Wildenberg, and owner George Janosik of the Waterbury, Connecticut company Eastern Color Printing – which (among other things) printed Sunday-paper comic-strip sections – produced Funnies on Parade as a way to keep their presses running. Like The Funnies but only eight pages, this appeared as a newsprint magazine. Rather than using original material, however, it reprinted in color several comic strips licensed from the McNaught Syndicate and the McClure Syndicate. These included such popular strips as cartoonist Al Smith's Mutt and Jeff, Ham Fisher's Joe Palooka, and Percy Crosby's Skippy. This periodical, however, was neither sold nor available on newsstands, but rather sent free as a promotional item to consumers who mailed in coupons clipped from Procter & Gamble soap and toiletries products. Ten-thousand copies were made. The promotion proved a success, and Eastern Color that year produced similar periodicals for Canada Dry soft drinks, Kinney Shoes, Wheatena cereal and others, with print runs of from 100,000 to 250,000.

Famous Funnies and New Fun.

Also in 1933 Gaines and Wildenberg collaborated with Dell to publish the 36-page Famous Funnies: A Carnival of Comics,   which historians consider the first true American comic book; Goulart, for example, calls it "the cornerstone for one of the most lucrative branches of magazine publishing". Distribution took place through the Woolworth's department-store chain, though it remains unclear whether it was sold or given away; the cover displays no price, but Goulart refers, either metaphorically or literally, to "sticking a ten-cent pricetag [sic] on the comic books".  When Delacorte declined to continue with Famous Funnies: A Carnival of Comics, Eastern Color on its own published Famous Funnies #1 (cover-dated July 1934), a 68-page giant selling for 10¢. Distributed to newsstands by the mammoth American News Company, it proved a hit with readers during the cash-strapped Great Depression, selling 90 percent of its 200,000 print — though putting Eastern Color more than $4,000 in the red. That quickly changed, with the book turning a $30,000 profit each issue starting with #12. Famous Funnies would eventually run 218 issues, inspire imitators, and largely launch a new mass medium.

When the supply of available existing comic strips began to dwindle, early comic books began to include a small amount of new, original material in comic-strip format. Inevitably, a comic book of all-original material, with no comic-strip reprints, debuted. Fledgling publisher Malcolm Wheeler-Nicholson founded National Allied Publications – which would evolve into DC Comics – to release New Fun #1 (Feb. 1935). This came out as a tabloid-sized, 10-inch by 15-inch, 36-page magazine with a card-stock, non-glossy cover. An anthology, it mixed humor features such as the funny animal comic "Pelion and Ossa" and the college-set "Jigger and Ginger" with such dramatic fare as the Western strip "Jack Woods" and the "yellow-peril" adventure "Barry O'Neill", featuring a Fu Manchu-styled villain, Fang Gow. Issue #6 (Oct. 1935) brought the comic-book debut of Jerry Siegel and Joe Shuster, the future creators of Superman, who began their careers with the musketeer swashbuckler "Henri Duval" (doing the first two installments before turning it over to others) and, under the pseudonyms "Leger and Reuths", the supernatural-crimefighter adventure Doctor Occult.

 Superheroes and the Golden Age

In 1938, after Wheeler-Nicholson's partner Harry Donenfeld had ousted him, National Allied editor Vin Sullivan pulled a Siegel/Shuster creation from the slush pile and used it as the cover feature (but only as a backup story)[8] in Action Comics #1 (June 1938). The duo's alien hero, Superman, dressed in colorful tights and a cape evoking costumed circus daredevil performers, became the archetype of the "superheroes" that would follow. Action would become the American comic book with the second-largest number of issues, next to Dell Comics' Four Color, with over 860 issues published as of 2008.

Siegel and Shuster's Superman, influenced by the pulp fiction stories and by the legend of the Golem of Prague, had superhuman strength, speed and other abilities, and lived day-to-day in his secret identity as a mild-mannered reporter named Clark Kent. Within two years, most comic-book companies had started publishing large lines of superhero titles, and Superman has gone on to become one of the world's most recognizable characters.

Aficonados know the period from the late 1930s through roughly the end of the 1940s as the Golden Age of comic books. It featured extremely large print-runs, with Action and Captain Marvel selling over half a million copies a month each; comics provided very popular cheap entertainment during World War II, but erratic quality in stories, in art, and in printing. Unusually, the comics industry provided jobs to an ethnic cross-section of Americans (particularly Jews), albeit often at low wages and in sweatshop working-conditions.

Following World War II the popularity of superhero comics rapidly declined. Publishers began to phase them out around 1945 and replace them with teen humor (epitomized by Archie Comics), funny animal comics (such as those featuring Walt Disney characters), science fiction, Western, romance, and satire comics. Timely's superhero line ended in 1950 when it canceled Captain America, which had already been converted into a horror title for its final issues. Except for National's Superman, Batman, and Wonder Woman, superheroes practically went extinct by 1952.

Comics as an overall genre continued to increase their readership into the 1950s, however, with Walt Disney's Comics and Stories selling almost three million copies a month in 1953). Close to a dozen Dell funny-animal titles sold over one million copies each per month. EC Comics' more adult-oriented horror titles sold 400,000 a month

http://en.wikipedia.org/wiki/American_comics