From the Browse Letters option at SoldierStudies.org: Several observations on the data, Union correspondences in the database far exceed Confederate; which is not unusual, but we hope to get more. New York leads all states whether Union or Confederate with 167. The top three are all Union: New York: 167 Pennsylvania: 145 Massachusetts: 136 The data represents the declared state (including: Territory, Regular Army, US Colored ,ect.), unit, and allegiance…