A flint mine is an industrial site where, during Neolithic and early Bronze Age times, nodules of flint were extracted by hand from underground seams within the Upper Chalk. Flint mines thus comprise one or more pits or shafts together with associated spoil heaps and working floors. The flint extracted from these mines was used for making a variety of tools and implements, including axes and adzes.

Flint mines are mostly known from surface features, notably the roughly circular depressions up to 20m across which mark the mine shafts juxtaposed with the humpy ground caused by overlapping spoilheaps. Such features may be identified from ground level surveys or from aerial reconnaissance. Flintworking debris, particularly debris from the primary stage of working, may also provide clues to the presence of a flint mine.

Flint mines are fairly easily confused with a range of more recent classes of monuments, notably chalk quarries, marl pits, deneholes and chalk tunnels. These can usually be distinguished by the presence of a trackway leading to them; such tracks are absent from Neolithic flint mines. Other possible sources of confusion include pond barrows, shafts, bomb craters, and ponds of various classes. Carefully attention to detail is sometimes required to separate these monuments, but a first step when authenticating any propospective flint mine is to check that it lies on Upper Chalk because this is the only geological solid in which natural seams of flint occur in England.

Specifically excluded from the definition of flint mines are the working sites dependent upon flint nodules eroding from, or quarried from, the face of a natural cliff or rock exposure.

Flint mines provided a very important source of material for the manufacture of edged tools in the millennia before the widespread availability of metal, and in some cases continued to be used even after metal had been introduced.