R.A. Rowan & Co. was founded in 1904 by 28-year-old Robert Rowan, having been involved in Los Angeles real estate for seven years. (A real estate article in the Los Angeles Times (1903) mentions Edward L. Doheny buying a lot at Main and 5th Street from Mrs. M. Lee-- with R.A. Rowan as the agent.) By 1918 the company had built more buildings downtown than anyone else in the business.

The Rowan company was responsible for the first landmark building erected in Los Angeles, the Alexandria Hotel, which established the downtown "financial district" comprised of the intersection of 5th and Spring streets and the surrounding area. The Los Angeles Athletic Club, the Rosslyn Hotel, and Windsor Square (residential development) were also early Rowan development projects.

The second generation of Rowans in real estate converted the company from strictly a land developer to a service entity. In addition to its commercial real estate brokerage operations, R.A. Rowan & Co. established a property management department and related service functions. In the early 1940s, the Rowan company acquired farmland in the central San Joaquin valley, expanding its scope of development activities even further. (At the same time, Rowan opened a branch in Phoenix, Arizona, specializing in the sale of extensive ranch properties.)

By the late 1960s, the Rowan family had acquired the William Wilson Company in Pasadena. Founded in 1887, it was the oldest and largest residential real estate firm in Pasadena, and one of the oldest and continuously operated residential brokerages in the state. With offices in downtown Pasadena, West Pasadena, Altadena, and San Marino, the Wilson company also served La Cañada, Flintridge, and Arcadia. In the 1970s, R.A. Rowan & Co. moved its corporate headquarters from 458 S. Spring Street (where it had been since 1917) to 180 S. Howe Street in Pasadena.

In the early 1980s, the “third generation” of Rowans in real estate—as it was largely still a family business—expanded its commercial real estate brokerage even further where it evolved into the Rowan Group. The Rowan Group was comprised of several subsidiaries including Rowan Projects, Inc. (property development); Rowan Services, Inc. (janitorial and emergency services); Louis Rowan & Co. (insurance services); the William Wilson Company (residential real estate); R.A. Rowan & Co. and South Boston Co. (agriculture); Summit Lake Farm (thoroughbred breeding and management); and Rowan Vineyards (based in Santa Barbara County).

By the 1990s, however, the Rowan empire had begun to dissipate—the reason or reasons are not obvious from the records—but in 1993 liquidation agreements were signed by several remaining Rowan family members (directors) and Robert Wilson for the Louis Rowan & Co. and the William Wilson Co., with the other groups presumably dissolved by the end of the decade.

Today the Rowan Building, built in 1912 at 5th and Spring streets, is home to the upscale Rowan Building Lofts. The iconic Beaux-arts landmark in L.A.’s downtown historic core, was built by renowned architects John Parkinson and Edwin Bergstrom who are also credited with other Los Angeles landmarks such as City Hall, the Pacific Stock Exchange, and the Alexandria Hotel.