In 1923 during the post-war boom, the local Chamber of Commerce decided to advertise the city's welcoming attitude toward industry on a hillside overlooking the city. The first whitewashed sign, reading "South San Francisco the Industrial City," was replaced six years later by a larger, more permanent sign bearing the same message. The choice of a hillside sign to advertise the city can be seen as an outgrowth of two civic boosting traditions: the electric Main Street slogan sign, and the hillside letter.

The South San Francisco Hillside Sign consists of large, flat concrete letters, painted white, set on the southern side of a steep, 581 foot high hill, that forms part of the San Bruno Mountains. A series of concrete footings are located higher on the hill, the remainder of an electric sign dating from the 1930s.

Both the sign and the foundations are within the 41 acre Sign Hill Park, an area maintained by the city of South San Francisco. Although the foundations are obviously ruins (and are not being counted), the primary sign maintains a high degree of integrity, protected as it is within a relatively undeveloped park setting.

The hillside sign forms three lines on the hill. The first line, reading "SOUTH," is 166 feet long; the second, reading "SAN FRANCISCO," is 484 feel long; and the third, "THE INDUSTRIAL CITY," is 628 feet long.

The letters themselves range in height from 48 to 65 feet, in an anamorphtc arrangement on the contoured hill to create the illusion, from a distance, of straight, regularly-sized and spaced text. Individual legs of the letters are approximately ten feet wide. Letter width varies from a ten foot wide "I" to a 22 foot, 8 inch wide "S." The thickness of the letters appears to be no more than three or four inches, with approximately two inches on average rising above the ground.

Excerpted from the NRHP nomination.