...Sheriffs were generally allowed to hire assistants or deputies to help with the day to day responsibilities of his office. He was also allowed to appoint citizens to perform certain functions to preserve the peace. The posse comitatus, or power of the county, enabled sheriffs to summon aid. An 1861 Colorado statute formally called for this procedure:
"When any felonious offense shall be committed, public notice thereof shall be immediately given in all public places near where the same was committed, and fresh pursuit shall forthwith be made after every person guilty thereof by sheriffs, coroners, constables, and other persons who shall be by any of them commanded or summoned for that purpose"
Wyoming allowed for sheriffs to use a residence for his law enforcement purposes at county expense. New Mexico extended jurisdictional limits of the sheriff to permit him or his deputies to enter all counties in the state to affect an arrest and to have concurrent rights of posse comitatus in every county. While the duties of sheriffs and their deputies were multitudinous, the primary law enforcement functions were virtually identical throughout the early West. . . .
As chief law enforcement officer of the county, the sheriff performed diverse duties. In many jurisdictions he served as tax collector, similar to the duties of the colonial sheriff. Also in contrast to its colonial forerunner, the sheriff had to administer corporal punishment, as directed by the courts. The sheriff often times was required to carry out the sentence of death. Rustic executions in the Wild West were performed primarily by hanging an offender. Sometimes sheriffs constructed formal gallows for this purpose, and other times a rope was simply tossed over a stout tree limb to accomplish the execution. Other duties of the office were rather mundane and involved the service of process or other civil enforcement functions . . . .
http://www.correctionhistory.org/html/chronicl/sheriff/ch13.htm