Elgin County (/ˈɛlɡɪn/ EL-ghin) is a county composed of seven municipalities in Ontario, Canada with a 2021 population of 51,912.

Its population centres are Aylmer, Port Stanley, Belmont, Dutton and West Lorne.

Elgin County is composed of seven incorporated municipalities (in order of population): The City of St. Thomas is geographically within the boundaries of Elgin County and part of the Elgin census division, but is separated from county administration.

The County was separated from Middlesex in September 1853.

[4] As a census division in the 2021 Census of Population conducted by Statistics Canada, Elgin County had a population of 94,752 living in 37,278 of its 38,889 total private dwellings, a change of 6.5% from its 2016 population of 88,978.