Mount Helix, California

The same ground, surveyed 103 years apart. Drag the handle to wipe between them. Both sheets are United States Geological Survey originals; neither has been altered.

1893 1996

Matched by testing this settlement's coordinate against the published boundary of every sheet in the United States Geological Survey's historical collection. Each opens the scanned sheet at the Survey.

• 1893 USGS El Cajon quadrangle1:62500
• 1893 USGS Elcajon quadrangle1:62500
• 1901 USGS Elcajon quadrangle1:62500
• 1903 USGS Cuyamaca quadrangle1:125000, 6 printings
• 1903 USGS El Cajon quadrangle1:62500, 2 printings
• 1903 USGS Elcajon quadrangle1:62500, 3 printings
• 1904 USGS Southern California Sheet No. 2 quadrangle1:250000, 5 printings
• 1939 USGS El Cajon quadrangle1:62500, 2 printings
• 1942 USGS El Cajon quadrangle1:62500
• 1947 USGS El Cajon quadrangle1:62500
• 1950 USGS San Diego quadrangle1:250000
• 1954 USGS San Diego quadrangle1:250000
• 1955 USGS El Cajon quadrangle1:24000, 2 printings
• 1955 USGS San Diego quadrangle1:250000
• 1958 USGS San Diego quadrangle1:250000, 4 printings
• 1967 USGS El Cajon quadrangle1:24000, 7 printings
• 1979 USGS El Cajon quadrangle1:100000, 2 printings
• 1996 USGS El Cajon quadrangle1:24000

Regional context, not property-specific evidence. The federal wildfire occurrence database lists 472 fires within 5 miles of Mount Helix between 1992 and 2020, burning about 695 acres in total. 1 started naturally. 64 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.

The most recent of them, most recent first, with the day each was reported and the service that recorded it.

Settlements close enough to share some of these fires:

• Alta (historical)
• Grossmont
• Cajon Heights
• Calavo Gardens
• Casa de Oro
• La Mesa

Every fire recorded in San Diego County

Regional context, not property-specific evidence. The federal mineral resources record lists 39 workings within 5 miles of Mount Helix: 21 past producers, 15 producers, 1 occurrence, 1 prospect. 15 still produce. What was taken out: Granite, Stone, Crushed/Broken, Sand and Gravel, Construction, Gold. Distance is straight-line from the map coordinates, so a quarry counted here may appear on a neighbouring settlement's page as well.

Every working recorded in San Diego County

The eight closest, with where each one stands in the county. Distances are straight-line, computed from the Geographic Names Information System coordinates.

This settlement is recorded in the Geographic Names Information System as feature 1869778. The sheet list is computed by point-in-boundary test against the United States Geological Survey's historical topographic inventory. Both are works of the United States government and carry no copyright under 17 U.S.C. 105.

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.