Union School/Xenia Township #10. Union Rd at Bell Rd. You can see the very edge of the Union United Methodist Church across the street.
Another view of the old school building is here:https://vintageaerial.com/photos/ohio...

School built ca. 1890s [1900 is often a placeholder date] - closed February 24, 1950

Jhef_1; thanks for the additional info! The Greene County Auditor's digital records list any building built prior to 1900 as 1900.

Interestingly, sometimes the 1900 placeholder winds up on buildings built some time later*; I wonder if it became common due to 1900 being an epoch/default date for many computer applications for years, if it wasn't already being used as a placeholder prior to computerized records.

Turns out 1900 is, in fact, an epoch date for certain software applications [even if it doesn't make sense for the area]. Some counties have "old" instead of "1900" as a placeholder, as their auditor/GIS system uses different software.

*I've seen "1900" appears on the record of a building built 1901, maybe 1910 in some cases; I've seen "1902" specifically on 1870s and 1880s buildings, and there's always human error, etc.