many historians are beginning to accept that the earlier death estimates were probably far too low. a demographic historian from new york's binghamton university, j. david hacker, has made a new calculation of civil war deaths which is about 20% higher. the new estimate is 750,000 deaths and is based on digitized nineteenth century census data. the population of the united states in 1860 was just under 31.5 million. approximately 2,000,000 men served in the union forces while about 750,000 served in the confederacy. about 75% of soldiers were born in america. of the remaining 25% who were foreign born, many did not appear in any census records prior to the civil war.