Cheshire is a county in England. It was originally "
Chester shire",
shire being an old word for "county" or "district". Cheshire was named after the town of
Chester, and that place name is from Old English
caester, "town or city founded by Romans", which in turn is from the Latin word
castra, "camp (for
Roman soldiers)".
This information is mostly from
A Dictionary of English Place-names by A. D. Mills.