Atlantic City was not a town that grew gradually. It was assembled in 1854 by a railroad. Dr. Jonathan Pitney, a local physician, had been advocating for years that the long, narrow Absecon Island would make a perfect health resort - the sea air, the south wind, the unbroken Atlantic horizon. He convinced the Camden and Atlantic Railroad to build a line. The town's grid was laid out by surveyor Richard Boyse Osborne in 1853, and the streets were given names that would become famous to anyone who has played the board game Monopoly: Baltic, Mediterranean, Connecticut, Vermont, Pennsylvania, Park Place. The first train arrived July 1, 1854. The first hotel, the United States Hotel, opened the same year. Within a decade, Atlantic City was the closest seaside resort to Philadelphia, and the railroads were running excursion trains in volume.

By the early twentieth century Atlantic City had become something close to America's national vice capital. Prohibition was passed in 1919 and ignored locally; the local political boss, Enoch "Nucky" Johnson, ran the city through the 1920s as an open city for gambling, liquor, and prostitution. The HBO series Boardwalk Empire dramatized the era - and the dramatization, while compressed for television, was substantially accurate. Johnson held the formal title of Atlantic County Republican Committee chairman and the informal title of boss. He was convicted of tax evasion in 1941 in a federal prosecution that bore strong resemblances to Al Capone's. The city's political machine had run things since the late nineteenth century and would continue to run them, in different forms, into the 1970s. The Boardwalk Empire era left an architectural legacy: many of the grand hotels still standing today were built or substantially remodeled during the 1920s.

After World War II, Atlantic City declined faster than almost any other American resort city. Air travel made Florida and the Caribbean more attractive. Air conditioning made northern summers tolerable, reducing the seaside demand. The 1964 Democratic National Convention, held at Convention Hall, was supposed to showcase a revitalized city but instead exposed widespread urban decay to television cameras. By the 1970s much of Atlantic City was abandoned - hotels boarded up, sections of the boardwalk closed, population dropping. The city's last best hope, the casino legalization referendum, passed in 1976 by a narrow margin - the result of years of campaigning by Atlantic City political and business leaders who argued that gambling was the only thing left that could save the city.

On May 26, 1978, Resorts International Hotel and Casino opened as the first legal East Coast casino. The lines on opening day stretched around the block. Resorts made $134 million in its first year - more than any Las Vegas casino. A wave of construction followed: Caesars in 1979, Bally's Park Place in 1979, the Sands in 1980, Harrah's Marina in 1980, Trump Plaza in 1984, Trump's Castle in 1985, Trump Taj Mahal in 1990. By 1990, Atlantic City had eleven major casinos and was the second-largest gambling destination in the United States after Las Vegas. The casino boom transformed the boardwalk skyline. It did not, however, transform the rest of the city - the casinos sat behind walls of parking garages and concentrated their economic activity inward. Beyond the casino district, much of the older city continued to decline.

Hurricane Sandy made landfall just south of Atlantic City on October 29, 2012. The boardwalk damage was much-discussed but mostly limited to the northern residential section already slated for demolition. The bigger damage was economic. The same year, Pennsylvania casino gambling - legalized in 2004 - hit Atlantic City harder than the storm. By 2014, four Atlantic City casinos had closed within a single year: the Atlantic Club, Showboat, Revel, and Trump Plaza. The city itself filed for receivership in 2016 and went under state financial control. The remaining casinos have stabilized. The boardwalk has been rebuilt. New non-gaming attractions - the Steel Pier amusements, the Hard Rock and Ocean casinos, the ACX1 Studios film complex - represent attempts to broaden the city's appeal beyond the casino floor. Whether the city ever recovers what it once was depends largely on whether enough people still want what Atlantic City still offers.