The length of the old English mile has been hitherto so uncertain, that any fresh light upon it is well worthy of study; and an important source of information—the map in the Bodleian Library— has not yet been brought to bear upon the question. The present inquiry was suggested by the sight of this map, which seems to add so much to our knowledge that a review of the whole subject has become desirable. It is proposed, therefore, in this paper to bring together all the data worth consideration, beginning with the most recent; and by deducing what the mean conclusion is from each source, to be thus able to compare together the various results, and so arrive at some definite statements within known limits of uncertainty.