Abstract The Southern Pacific Milling Company (SP Milling) was primarily a milling and quarrying company that had operations in several locations throughout California’s central coast, with major operations in El Rio and in Ventura. The company was active from around 1886 to 1995. In the 1950s the company took over the business of the Santa Barbara Mill and Lumber Company. In the 1960s, SP Milling and a subsidiary became more involved in the quarrying, concrete and gravel businesses. This collection...