Question: The Pleiades supercomputer is housed in a facilities in what county?

Context paragraphs:
University of London Computer Centre: The University of London Computer Centre (ULCC) was founded in 1968, and was the first supercomputer facility established in London for the purpose of scientific and educational research by all of the colleges of the University of London.  ULCC initially provided large-scale CDC-based facilities, then from 1982 to 1991 a national Cray vector supercomputing service, and, latterly, a 6 processor, 4 Gbyte Convex C3860 supercomputer with a Convex C3200 front-end.

Eris (simulation): Eris is a computer simulation of the Milky Way galaxy's physics.  It was done by astrophysicists from the Institute for Theoretical Physics at the University of Zurich, Switzerland and University of California, Santa Cruz.  The simulation project was undertaken at the NASA Advanced Supercomputer Division’s Pleiades and the Swiss National Supercomputing Centre for nearly eight months, which would have otherwise taken 570 years in a personal computer.  The Eris simulation is the first successful detailed simulation of a Milky Way like galaxy.  The results of the simulation were announced in August 2011.

Moffett Federal Airfield: Moffett Federal Airfield (IATA: NUQ, ICAO: KNUQ, FAA LID: NUQ) , also known as Moffett Field, is a joint civil-military airport located in an unincorporated part of Santa Clara County between northern Mountain View and northern Sunnyvale, California, USA.  On November 10, 2014, NASA announced that it would be leasing the airfield to Google for 60 years.

Pleiades (supercomputer): Pleiades ( or ) is a petascale supercomputer housed at the NASA Advanced Supercomputing (NAS) facility at NASA Ames Research Center located at Moffett Field near Mountain View, California.  It is maintained by NASA and partners Silicon Graphics (SGI) and Intel.

Supercomputer Education Research Centre: Supercomputer Education Research Centre The Computer Centre, established in 1970 as a central computing facility, became Supercomputer Education and Research Centre (SERC) in 1990 to provide state-of-the-art computing facility to the faculty and students of the Institute.  The Centre is conceived of as a functionally distributed supercomputing environment, housing leading-edge computing systems, with sophisticated software packages, and connected by a powerful high-speed fibre-optic network.  The computing facilities are connected to the campus LAN, WLAN and also to the Internet.  The Centre was created to commemorate the Platinum Jubilee of the Institute, in the year 1984.

Kraken (supercomputer): Kraken was a Cray XT5 supercomputer that entered into full production mode on February 2, 2009.  Kraken was operated by the University of Tennessee and was the most powerful computer in the world managed by academia at the time.  It was housed in the Oak Ridge Leadership Computing facility at Oak Ridge National Laboratory.  Kraken was decommissioned on April 30, 2014.

SuperMUC: SuperMUC is the name of a supercomputer of the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences.  It is housed in the LRZ's data centre in Garching near Munich.

Bolshoi Cosmological Simulation: The Bolshoi simulation, run in 2010 on the Pleiades supercomputer at the NASA Ames Research Center, was the most accurate cosmological simulation to that date of the evolution of the large-scale structure of the universe.

HPCx: HPCx was a supercomputer (actually a cluster of IBM eServer p5 575 high-performance servers) located at the Daresbury Laboratory in Cheshire, England.  The supercomputer was maintained by the HPCx Consortium, UoE HPCX Ltd, which was led by the University of Edinburgh: EPCC, with the Science and Technology Facilities Council and IBM.  The project was funded by EPSRC.

GravitySimulator: gravitySimulator is a novel supercomputer that incorporates special-purpose GRAPE hardware to solve the gravitational "n"-body problem.  It is housed in the Center for Computational Relativity and Gravitation (CCRG) at the Rochester Institute of Technology.  It became operational in 2005.

Supporting paragraphs: Pleiades (supercomputer) Moffett Federal Airfield
Answer: Santa Clara County