X-100, Historic house in San Mateo, United States.

The X-100 is a steel-frame house built in 1956 at the San Mateo Highlands development, designed by A. Quincy Jones with Frederick Emmons for Eichler Homes. Six bents of 4-inch H-section columns and 8-inch I-beams support the roof; the beams are painted deep-tone cinnamon and the corrugated metal ceiling light grey. Three bedrooms and two living rooms surround a central utility core with two bathrooms, and two interior gardens replace the usual Eichler atrium.

Eichler Homes commissioned the X-100 from A. Quincy Jones in 1955 to test steel as a material for tract housing and to draw buyers to the remote San Mateo Highlands tract. Ground was broken in May 1956 and the house opened on October 6; it was listed on the National Register of Historic Places in 2016.

The name may come from the X-15 rocket plane, and the house was presented as the "house of tomorrow" for three months, drawing 150,000 visitors. It appeared in Popular Science, Life, Sunset and Arts & Architecture, and in a newsreel. A metal star sculpture on the facade is probably by Matt Kahn, an artist who worked with Eichler.

The house is visible from the street and sits in a residential neighborhood in San Mateo. Visitors should respect the privacy of current residents and view the property from public areas.

A metal star sculpture on the facade is probably by Matt Kahn, an artist who worked with Eichler. The house was displayed for three months as the "house of tomorrow" and drew 150,000 visitors, and it appeared in Popular Science, Life, Sunset and Arts & Architecture.