Located in Roscoe Township, Section 14, Township 37N, Range 27 W.
Oyer had a Post Office during the years 1882-1935.
Our Storehouse of Missouri Name Places, page 68:
Oyer in Roscoe Township, St. Clair Co., Missouri was named for William Oyer, postmaster in 1886. Location is the southwest section of the county, five miles west of Roscoe.