Built in 1916 (Beaux-Arts). Listed on the National Register of Historic Places in 1975. 22 historic topographic surveys show this location, the earliest from 1892.
From the record
“Carolands Chateau is a 46,050-square-foot (4,278 m2), 4.5 floor, 98 room mansion on 5.83 acres (2.36 ha) in Hillsborough, California, United States. An example of American Renaissance and Beaux-Arts design, the building is a California Historical Landmark and is listed on the National Register of Historic Places.”
Wikipedia article Carolands, CC BY-SA 4.0.
One of 63 National Register listings published here for San Mateo County · listed in 1975 · category: Building · built in 1916, Beaux-Arts, by Ernest Sanson.
National Register reference number.75000478- the number the National Park Service assigned this property when it was listed, and the key its nomination file is catalogued under at the National Archives.
Then and now
1892 to 1997
The ground this property stands on, surveyed
105 years apart. Drag the handle to wipe between them. Both sheets are
United States Geological Survey originals; neither has been altered.
18921997
Fires near this property
266 since 1992
Regional context, not property-specific
evidence. The
federal wildfire occurrence database
lists 266 fires within 5 miles of Carolands, The
between 1992 and 2020, burning about 174 acres in total. 4 started naturally. 22 were recorded as arson.
Distance is straight-line from the map coordinates, so a fire counted
here may appear on a neighbouring settlement's page as well.
Reported cause
Fires
Missing data/not specified/undetermined
135
Equipment and vehicle use
51
Smoking
26
Arson/incendiarism
22
Misuse of fire by a minor
14
Debris and open burning
6
Power generation/transmission/distribution
4
Recreation and ceremony
4
Natural
4
The most recent of
them, most recent first, with the day each was reported and the service
that recorded it.
Date
Cause
Size
Reported by
Name on the report
9 September 2010
Missing data/not specified/undetermined
1.0 acres
California Department of Forestry & Fire Protection
not named
9 September 1999
Natural
under an acre
San Mateo-Santa Cruz Unit
SCARPER
9 September 1999
Natural
under an acre
San Mateo-Santa Cruz Unit
PILARCITOS
7 September 2020
Missing data/not specified/undetermined
under an acre
San Mateo-Santa Cruz Unit
not named
7 September 2009
Arson/incendiarism
under an acre
California Department of Forestry & Fire Protection
not named
7 September 2007
Smoking
under an acre
California Department of Forestry & Fire Protection
not named
5 September 2008
Equipment and vehicle use
under an acre
California Department of Forestry & Fire Protection
Regional context, not property-specific
evidence. The federal mineral resources record lists
24 workings within 5 miles of Carolands, The: 13 past producers, 10 producers, 1 unknown.
10 still produce. What was taken out: Stone, Crushed/Broken, Sand and Gravel, Construction, Calcium, Stone. Distance is straight-line from the
map coordinates, so a quarry counted here may appear on a neighbouring
settlement's page as well.
Regional context, not property-specific
evidence. The National Weather Service names
Hillsborough, the town this property stands in, in 1 storm report in 2025: 1 flood.
No death or injury is recorded in these reports. Each account below is quoted exactly as the forecast office
filed it, from the NOAA Storm Events Database, and each date
opens the federal record of that event.
United States Geological Survey topographic
sheets whose coverage includes this point. Matched by taking the coordinate the National Park Service records for this property, then
testing that coordinate against the published boundary of every sheet.
Other National Register properties close
enough to walk or drive between, ordered by distance from this one. Both
positions come from the same geocoding pass that matched these properties
to their map sheets.
Listing record. National Park Service National Register of Historic Places, listed-properties dataset, current to 2026-05-22.
Map join. Address geocoded through the United States Census geocoder, then tested against the published boundary of every sheet in the USGS Historical Topographic Map Collection.
How this page is made. Listing fields come from federal records; map-sheet coverage is a labelled coordinate-to-boundary calculation, not a source-field claim.
Wildfire. Short, Karen C. 2022. Spatial wildfire occurrence data for the United States, 1992-2020 [FPA_FOD_20221014]. 6th Edition. Fort Collins, CO: Forest Service Research Data Archive. https://doi.org/10.2737/RDS-2013-0009.6 Collected with United States Government funding and usable without additional permissions or fees.
Mines and quarries. USGS Mineral Resources Data System (MRDS) https://mrdata.usgs.gov/mrds/ A work of the United States government, no copyright under 17 U.S.C. 105.
Storms. NOAA National Centers for Environmental Information, Storm Events Database https://www.ncei.noaa.gov/stormevents/ A work of the United States government, no copyright under 17 U.S.C. 105. Narratives are quoted verbatim from the National Weather Service report and are not edited or summarised.
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