Research on questions such as whether national leaders use force in the international arena to divert attention from problems at home depends on a valid and reliable list of the incidents in which various states have used military force. In the case of the United States, several data sets have been used for this purpose. This research note compares two widely used data sets, the militarized interstate disputes (MID) data, which cover disputes involving all states between 1816 and 1992, and the data originally compiled by Stephen Kaplan and Barry Blechman, which cover only the United States since World War II. This comparison indicates that, in spite of its usefulness for other conflict research, the MID data are not appropriate for analyses of U.S. decisions to use force, including tests of the diversionary hypothesis. The MID data set excludes several categories of incidents relevant to major theoretical arguments about the use of force and includes many irrelevant incidents. These problems are likely to apply to similar analyses of other states as well. The Blechman and Kaplan data set also excludes some relevant events, but its omissions are less consequential. We offer a revised list of United States uses of force between 1870 and 1995.