However, he had been forced to stop in the Isthmus of Panama for six months to recover from an illness he contracted.

Upon his arrival in San Francisco, many of the good mining sites had already been claimed,[1] so he opened an auction house instead.

[2] In 1870, when he and his partners sold the company to Southern Pacific Railroad, he joined its board of directors.

After railroads, Newhall turned his eye to auctioneering, real estate and ranching.

The most significant acquisition was the historic land grant 46,460-acre (188 km2) Rancho San Francisco in the Santa Clarita Valley of northern Los Angeles County, which he purchased for $2/acre.