St Olaf's Church in Wasdale Head, Cumbria, is England's smallest parish church. The earliest record of the church is from 1550, though it probably predates this, and it is likely that there was an earlier church on this site.
Wikipedia https://en.wikipedia.org/wiki/Church_of_St_Olaf,_Wasdale
Address (Unnamed Road), CA20 1EX, United Kingdom
Coordinates 54°28'1.555" N -3°15'12.812" E