It is named for Miguel Antonio Otero, the territorial governor when the county was created.

[3] Otero County includes the Alamogordo Micropolitan Statistical Area.

[4] The western part of Otero County was handed over to the United States Army as the US was preparing to enter World War II and eventually became part of White Sands Missile Range.

[citation needed] The county declared a state of emergency in April 2019 when the federal inspection stations on U.S. Route 70 and U.S. Route 54 were left unstaffed by U.S. Customs and Border Protection as part of the temporary closure of all six checkpoints in the El Paso Sector, which covers West Texas and New Mexico.

The county was concerned about the possibility of illegal narcotics flowing north unchecked since the checkpoint agents had been shifted to the border to help process migrant asylum-seekers.

[6] In response, the New Mexico Secretary of State filed a lawsuit and writ of mandamus against the commissioners for their refusal.

By Friday June 17, 2022, two of the three commissioners agreed to certify the election results, which defused the crisis.

23.30% of all households were made up of individuals, and 8.10% had someone living alone who was 65 years of age or older.

[18] School districts in the county include:[19] While the southeast portion of the county is in the Alamogordo district, that district contracts education of residents there to the Dell City Independent School District of Dell City, Texas,[20] due to the distances involved, as the mileage to Alamogordo from the former Cienega School was 100 miles (160 km) while the distance to Dell City is 20 miles (32 km).