December 2011
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San Gabriel Mountains may be growing in size

The GNIS viewer

No – not literally (although an earthquake could make that happen).  What is happening is that someone has made a suggestion to extend the definition of the San Gabriel Mountains further to the northwest than they currently are.  This happens in LA County once in a while, so I thought I’d pass things along as a little instruction on how things get named the way they are.  It turns out there’s a process for that, and after a while these things come to me.

“The U. S. Board on Geographic Names (GNIS) is responsible by law for adjudicating decisions regarding geographic names for use by the departments and agencies of the Federal government.  The Board has received a proposal to change the extend the application of the name San Gabriel Mountains to encompass a larger area extending to the northwest to include Liebre Mountain, Sierra Pelona and Sawmill Mountain. Because local opinion is very important to the Board, we would like the County’s opinion concerning the proposed application change.”


I extracted the relevant information from the USGS GNIS document (here’s a link to the extracted version) – it’s part of Review List 407 (link to the full GNIS list) .

A link in that document which (strangely) has a bunch of dots on it rather than a boundary (I took a snapshot and show it on the top right), with one of them in the City of Santa Clarita.  Click here to see the USGS provided map.  This is my primary concern with the definition – the range is defined as a series of dots, not as a true boundary.  As well, the dots as provided by the GNIS committee don’t appear to cover the full extent of the suggested boundary.

san gabriel mountains (my version)

I went ahead and created a draft of what I think the suggested boundary is using Google Maps:  My map of the San Gabriel Mountains extension.  There is a snapshot of that to the right.

My response
The County does not use the “San Gabriel Mountains” for administrative or mapping purposes (we use the Angeles National Forest), so we don’t have an opinion.  But I’d love to get yours!
In general, the San Gabriel Mountains themselves have an interesting and contradictory history in terms of naming and definition, and it appears that this update to their boundary is designed to follow a geologic description (which is a logical design).  My primary concern is that a draft boundary for the range has not been provided.  Rather the new definition is a series of locations, and the USGS doesn’t appear to have completely capture in its supporting documentation since they don’t extend to Sawmill Mountains (near Mount Pinos) on the northwest part of this definition.  Without a defined boundary it is hard to determine the relationship between this new geographic definition for the San Gabriel Mountains and the Topatopa Range and the Santa Susana Mounatins.

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