What is the place of origin of the "California Golden
Poppy(Eschscholzia californica)"?
We were recently in Peru and this flower is all over the place in
rather high altitudes(over 11,000 feet).   I saw some vague references
to it being native to Peru, but if you Google it, many of the results
say it's native to California...

It is very likely that California is its place of origin. The
following site belongs to someone whose research specialty is the
Eschscholzia genus; the site has distribution maps for more than a
dozen species for Eschscholzia - the ranges shown for the species are
in California and Mexico. With so many species having ranges in the
same area, it is likely that this is their native habitat.

http://www.csupomona.edu/~jcclark/poppy/species.html

It would be odd if a specialist in this species wouldn't know if the
California poppy was really an import.

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This USDA site

http://plants.usda.gov/cgi_bin/topics.cgi?earl=plant_profile.cgi&symbol=ESCA2

indicates that the California poppy is native to the U.S.: "U.S. Nativity: native."

Further down on that page, the USDA notes that the California poppy is invasive:

"California poppy 
This plant is considered invasive by the authoritative sources noted below."

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The Columbia Encyclopedia indicates that the poppy family is (mostly?)
from the Northern Hemisphere:

"POPPY [poppy] common name for some members of the Papaveraceae, a
family composed chiefly of herbs of the Northern Hemisphere having a
characteristic milky or colored sap. Most species are native to the
Old World; many are cultivated in gardens for their brilliantly
colored if short-lived blossoms. Many of the species have several
varieties and show a wide range of colors, especially in red, yellow,
and white shades. The true poppy genus is Papaver, but many flowers of
related genera are also called poppies. The most frequently cultivated
are the Oriental poppy ( P. orientale ), usually bearing a large
scarlet flower with a purplish black base, and the corn poppy ( P.
rhoeas ) and its variety, the Shirley poppy. Other well-known species
include the arctic Iceland poppy ( P. nudicaule ), the celandine poppy
( Stylophorum diphyllum ) of North America, and the cream cups (
Platystemon californica ) and California poppy, or eschscholtzia (
Eschscholtzia californica ), of the W United States (the latter is the
state flower of California)."

The above is from the site:

http://www.highbeam.com/ref/doc3.asp?docid=1E1:poppy

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The following doesn't prove that the California poppy arose elsewhere,
but does show that the genus name was given when the plant was seen in
California:

"Taxonomic history of Eschscholzia

Although the California poppy had surely already been seen by
Europeans, perhaps by members of the Cabrillo expedition in 1542, and
almost certainly by the late 1700s, it was first described by Adelbert
von Chamisso (1820) based on a collection from San Francisco in 1816.
Chamisso was the naturalist on the Russian ship Rurik, captained by
Otto von Kotzebue. The Rurik landed in San Francisco in October, and
the California poppies were among the few plants still in flower.
Chamisso named the genus in honor of Johann Friedrich Eschscholtz, the
expedition's physician and Chamisso's close friend."

This is from:

http://www.csupomona.edu/~jcclark/poppy/history.html

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A search for "poppy" and "peru" turned up references mostly to growing
the opium poppy (Papaver somniferum) and coca in Peru for illegal
drugs.

Since Eschscholzia californica is invasive and readily naturalizes,
perhaps they were planted as a garden flower (but at 11,000 feet?) and
escaped into the wild or someone bought poppy seeds, not knowing that
there were more poppies than the opium poppy?