However, a series of events caused virtually all permanent settlements to be abandoned between 1200 and 1300, and the area was contested between nomadic Ute and Navajo bands until resettlement occurred in the 1870s.

It was named in honor of Moctezuma II, who reigned as emperor of the Aztec Empire in Mexico during its decline at the hands of the Spanish invasion.

The building ruins in Mesa Verde National Park were thought to be of Aztec origin at the time.

Much of the county is irrigated cropland, and it produces fruit, large numbers of cattle and sheep, and beans.

The "border" with San Juan County, Colorado, is, however, only a point of zero length.

In its early history Montezuma County favored the Democratic Party.

Recently (July 28, 2020), the county government has openly endorsed viewpoints described as far-right[specify] by posting web links under a "News" banner on the official county web page.

[12] The last Democratic senatorial candidate to carry Montezuma County was Ben “Nighthorse” Campbell – later to switch to the Republican Party – in 1992.

[1] Prior to the redistricting, which took effect in the November 2022 election, Montezuma County was solely in House District 58.