The Hays Convention & Visitors Bureau has a nice webpage with some history of Hays.
The city of Hays and Fort Hays were named after Major General Alexander Hays, a Union general of the Civil War who was killed in the Battle of the Wilderness. The original Fort Hays was located south of Victoria. A flood on about June 3, 1867 washed out the fort and the fort was relocated south of present day Hays across Big Creek on June 23, 1867. Hays City was established on November 23, 1867.
A note about Major General Alexander Hays
You may run across some documents which state that Fort Fletcher was renamed to Fort Hays in honor of Major General Issac G. Hays. These documents appear to be in error.
The history of Hays is documented in The Golden Jubilee of German-Russian Settlements of Ellis and Rush Counties, Kansas, August 31, September 1 and 2, 1926.
On July 4, 1876 the flag is hoisted over Fort Hays by Lieutenant Charles H. Brewster of the Seventh. Soon after, a group of men from Fort Levenworth settled near by. They were:
H. J. McGaffigan
P. W. Carrell
M. E. Joyce
J. V. Macintosh
On October 28, 1867, Kansas Governor Samuel J. Crawford organizes Ellis County. He appoints the following:
Pliny Moore, County
William Rose, County Commissioner
Judson E. Walker, County Commissioner
Capt James G. Duncan, County Clerk
Hays was declared the temporary county seat at that time.
On September 24, 1867, Kansas Governor Samuel J. Crawford appointed M. E. Joyce as notary public.
In 1872, four buffalo hunters from Freeport, Illinois settled north of Hays. They included:
In 1873 a colony from Wilkes-Barre, Pennsylvania settled near Hays. Among those settlers was:
George S. Grass
I. M. Yost
A. K. Christman
In 1879 a colony from Brooklyn, New York settled north and west of Hays. Among those settlers was:
William J. Haddock
A group from Medaryville, Indiana settled north of Hays in 1879. Included were:
H. L. Brown
Richard R. Freshour
J. C. Settles (might be Lettler)
Also in 1879, a group from Lorraine, Ohio settled east and north of Hays. They included:
H. D. Shaffer
D. E. Barnes
Mrs. Anna Shaw
C. C. Brosius
A colony from Ripon, Wisconsin settled in Hays in 1878. They later left Hays for Larned. They were:
W. D. Radford
F. M. Hopkins
John W. Weisensee