There are 40 Generals Currently on Active Duty. This does not count the Generals that are in the National Guard and Reserve who have been activated or otherwise. http://en.wikipedia.org/wiki/List_of_active_duty_United_States_four-star_officers
Many
1 full general, 5 lieutenant generals and about 60 major generals
5
4 star generals are in the US
300
The US Army had over 1,100 Generals during WW2.
two hundred and fifty six
3
Marshell
There were approximately twelve four star generals in the US Army during 1945. However, due to damaged records and other mitigating factors, a precise count on the total number of generals, from one star up, is nearly impossible to come by at this time.
There is no information on how many commanding generals President Lincoln had gone through by June 1863. General George Meade commanded the Union army and General Robert E. Lee commanded the Confederate army.