About Sheridan Co. My mother was born in 1910 in Birney MT but graduated from Sheridan High School. Perhaps our mothers knew each other. I have her high school year books and will look through them. I accidently took the Acme exit trying to go to Birney, however, I soon turned around and got back on I90 and found the Decker exit. I'll be out there this summer and will drive down to the cemetery. I'm from IA, but was born in Powell.