As most of the tech inclined people know, SQL (pronounce: Sequel) is Structured Query Language, the standard language for database access. But this cache is about a different SQL (pronounce: Sierra-Quebec-Lima) - the IATA code for San Carlos Airport.
http://www.sancarlosairport.org/sql-history/
San Carlos has hosted an airport since the earliest days of powered flight. Around the time of World War I, the San Carlos Flying Field was established by J. Paulding Edwards who constructed a five-plane hangar along what is now Terminal Way and he graded a five-acre field south to Cordilleras Creek. In those days, an “airport” was often a rectangular field of grass or packed dirt arranged so that a plane could always be landed into the wind.
The airport was moved to current location in 1948, and currently is a home for both business and public aircrafts, including emergency services.
The cache is on a trail close to the SQL boundary.