Hillside is an unincorporated community and a U.S. Post Office in Fremont County, Colorado, United States.

The Hillside Post Office has the ZIP Code 81232.

[2] Hillside is located at 38°15′54″N 105°36′46″W / 38.26500°N 105.61278°W / 38.26500; -105.61278 (38.264872,-105.612774).