All the "regular counties" were formed under a uniform set of laws when formed in the Colorado Territory, and those laws provided for electing the sheriff. This is also traditional in the vast majority of counties across the US, but not universal. Since those original 17 territorial counties, each time a new county has been formed by splitting an existing county into one or more additional counties, the new county has adopted the same elected sheriff system, except Denver in 1902 and Broomfield in 2001. Denver was the first combined city/county, and chose to appoint its sheriff, and Broomfield followed the Denver city/county model rather than the "regular county" model.

Any other county in Colorado or the USA could change their method of selecting the sheriff by adopting new laws, if they wished, and unless their state's constitution said otherwise.