This overdate was a result of the United States' insatiable demand for circulating minor coins during the final two years of World War I. There was a nationwide shortage of cents and nickels in 1917 and 1918 that resulted in uncommonly large outputs of these denominations. During the final quarter of 1917 the engraving department at the Philadelphia Mint was busy producing dies for both 1917- and 1918-dated coinage. One of the obverse dies for the Buffalo nickel received its first impression from a 1917-dated hub, but the second impression came from a 1918-dated hub. This die was then shipped west for use in the Denver Mint, where it produced an unknown small number of 1918/7-D nickels.

The 1918/7-D was discovered by numismatists in 1931, by which time the opportunity to acquire Mint State coins had long since passed. Despite diligent searching on the part of numismatists since that time, examples remain elusive in all grades. This is particularly true in Mint State, at which level David W. Lange (The Complete Guide to Buffalo Nickels, 2000 edition) accounts for only about two dozen examples, taking into account resubmissions at the major certification services.

The example to the left was sold by Stack's Bowers Galleries in the Larry H. Miller Auction, where it realized $216,000.