The two-building conglomeration is also arguably America's largest shopping complex at one location. It is located in King of Prussia, an area within Upper Merion Township, Pennsylvania, northwest of Philadelphia.

The mall was originally developed by the Kravco company, which still owns it today (the company is now known as Kravco Simon). The Plaza at King of Prussia, the oldest portion of the complex, opened in 1963 as a modest open-air shopping mall anchored by JCPenney, discount department store E. J. Korvette, and an ACME supermarket. The Plaza prospered and by the late 1970s had become a partially enclosed super-regional mall anchored by department stores JCPenney, Gimbels, and Wanamaker's.

Kravco recognized a demand for more upscale shopping in the northwest Philadelphia market in the late 1970s. The company embarked on a second mall, The Court at King of Prussia, to be constructed across the street from The Plaza. The Court opened in 1981 as a fully enclosed mall anchored by department stores Bamberger's (later in 1986 to become Macy's), Bloomingdale's, and Abraham & Straus (A&S). In addition, Sears was added to The Plaza around this time, and until the early 1990s the Plaza sported such stores as Woolworth's, Herman's World of Sporting Goods, and a Lionel "Kiddie City" toy store. Before being redesigned, The Plaza also featured two 1980's style video arcades, each named Spaceport, and The RKO Plaza movie theater which, in an era before multiplexes, had only one extra large 7m screen.

By the early 1990s, demand for luxury goods had grown across the nation and many upscale retailers were in a growth mode. Lord & Taylor, Neiman Marcus, and Nordstrom were all looking for new locations in the area, and Kravco didn't want any of them to land at a competing mall. The company's dilemma, though, was that The Court was on a small piece of land and couldn't expand, while The Plaza was too downscale for these stores. Kravco decided to embark on an ambitious campaign to almost completely rebuild The Plaza to make it just as attractive to upscale retailers as The Court and to begin marketing the two malls as a single entity (a pedestrian bridge and walkway connecting the malls was constructed around this time, though there have always been informal passageways from one to the other).

The new Plaza is fully enclosed and has two levels throughout. Lord & Taylor opened its doors in the fall of 1995, while Neiman Marcus and Nordstrom opened theirs in the spring of 1996. Upscale stores at The Plaza are clustered in the southern end of the mall near Lord & Taylor, Neiman Marcus, and Nordstrom, while middle-market stores remain clustered in the northern end of the mall near JCPenney and Sears. The Court now contains a mix of upscale stores and middle-market stores.

The anchor line-up at both malls changed during the 1990s. Stern's, which had replaced Gimbel's, left and JCPenney moved in to its old space. John Wanamaker was acquired by May Department Stores, which rebranded all Wanamaker's as Hecht's, their Baltimore-Washington regional nameplate. Abraham & Straus was consolidated with Macy's and Strawbridge & Clothier briefly took its place at The Court. Soon after, May acquired Strawbridge & Clothier, rebranded it as simply Strawbridge's, and merged it with Hecht's Philadelphia operations. The Hecht's (former John Wanamaker) at The Plaza became a Strawbridge's and the Strawbridge's (former Abraham & Straus) at The Court closed. The mall even featured an outlet of the popular New York City toy company F.A.O. Schwarz, complete with a giant teddy bear, before hard financial times forced it to close in 2004.

The growth of large-format specialty retailers in the 1990s led to the early 2000s conversion of the former Strawbridge's store at The Court into The Pavilion at King of Prussia, which might be considered the "third mall" at King of Prussia. The Pavilion consists of a small mall directly connected to The Court but is not owned by Kravco. Tenants at The Pavilion include The Cheesecake Factory, Borders, H&M, Urban Outfitters, DSW Shoes, Five Below, and Morton's, and The Steakhouse and many more.

In 2006, the Strawbridge's store was reflagged as a second Macy's location. It was closed in 2007, and future status for the building is undetermined. Currently it housed an exhibit of Norman Rockwell.

The upscale mall, anchored by Bloomingdale's, Lord & Taylor, Neiman Marcus, Nordstrom, JCPenney, Sears and Macy's, has over 400 stores and restaurants. It is also the sole outpost in Philadelphia for a number of high-end stores including Stuart Weitzman, Hugo Boss, Diesel, Betsey Johnson, Movado, Kate Spade, DKNY, Louis Vuitton, Cartier, Anne Fontaine, Tiffany & Co., an Apple Store, and Hermès. King of Prussia frequently sees the addition of new luxury stores, most recently signing David Yurman, Montblanc, Ralph Lauren, 7 for all Mankind, Thomas Pink, Salvatore Ferragamo, Piazza Sempione, Tory Burch, Henri Bendel, Michael Kors, and Gucci. At the same time, it also has popular teen clothing stores like Abercrombie & Fitch, Hollister Co., American Eagle Outfitters, Aeropostale, and H&M.

The mall is a prominent tourist destination in the Philadelphia area, with an estimated 20-25% of visitors as tourists. Several nearby hotels offer mall tourist packages, which typically include mall gift cards. The mall employs over 6,000 people in the area.