Blenheim Farm is a 1-hectare (2.5-acre) nature reserve near Charlbury in Oxfordshire. It is owned and managed by the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust.

This is a meadow surrounded by ancient hedges and woodland. Flora include common knapweed, lady's bedstraw, cowslip and ragged-robin, while there are butterflies such as the common blue and orange tip. Amphibians include common frogs, common toads and smooth newts.

51°52′19″N 1°28′22″W / 51.8720°N 1.4727°W / 51.8720; -1.4727