The text specifies the battalions to which new recruits would be attached on arrival:
1st, 2nd, 11th, 12th, & 13th – Alaska, Washington, Oregon and Idaho
3rd, 4th, 5th, 18th, 19th, & 20th – Northern California
6th, 7th, 8th, 14th, & 15th – Southern California
9th, 10th, 16th, & 17th – Nevada, Utah, Wyoming and Montana
21st – colored (sic)
The camp hospital, in which Captain W F Fitch MC died, is at the top left.
(Map Legacy Washington)