Upton Sinclair House, National Historic Landmark residence in Monrovia, California.

The Upton Sinclair House at 464 N. Myrtle Avenue is a poured-concrete Neo-Mediterranean residence built in 1923. Its entrance sits in an ornate round arch with an iron balcony above, flanked by round-arch windows, and the exterior carries ball-and-ribbon concrete moldings and Batchelder tile. A period garage stands at the rear right.

The house was constructed in 1923 and became home to a renowned author from 1942 until 1966. During his residency, the writer completed numerous works and stored important manuscripts in a concrete vault on the property.

Sinclair bought the house in 1942 to escape Pasadena and lived here until 1966, writing many later works in a studio built into the garage. He received the Pulitzer Prize for Fiction in 1943 while living here. The property is a private residence, so the house and its concrete paper vault can only be seen from the street.

The house is a private residence and is not open to the public; there is no arranged access. Visitors can view the exterior from North Myrtle Avenue at the corner of East Scenic Drive, in the foothills north of central Monrovia. The period garage and concrete vault are on the grounds and not visible from the street.

The 1991 Sierra Madre earthquake (magnitude 5.6) damaged the house, and its owner nearly had it torn down. California's state historic preservation office refused the demolition permit, so the building survived to keep its 1971 National Historic Landmark status.