center|thumb|Map of the states and territories claimed by the Confederate States of America|upright=2.0 Much of the area had a humid subtropical climate with mild winters and long, hot, humid summers. The climate and terrain varied from vast swamps to semi-arid steppes and arid deserts. The subtropical climate made winters mild but allowed infectious diseases to flourish; on both sides more soldiers died from disease than were killed in combat.Two-thirds of soldiers' deaths occurred due to disease.
center|thumb|Map of the states and territories claimed by the Confederate States of America|upright=20 Much of the area had a humid subtropical climate with mild winters and long hot humid summers The climate and terrain varied from vast swamps to semi-arid steppes and arid deserts The subtropical climate made winters mild but allowed infectious diseases to flourish; on both sides more soldiers died from disease than were killed in combatTwo-thirds of soldiers' deaths occurred due to disease