Riddle is an unincorporated community

Unincorporated area

In law, an unincorporated area is a region of land that is not a part of any municipality.To "incorporate" in this context means to form a municipal corporation, a city, town, or village with its own government. An unincorporated community is usually not subject to or taxed by a municipal government...

 in the southwestern

Southwestern Idaho

Southwestern Idaho is a geographical term for the area along the state of Idaho's borders with Oregon and Nevada. It includes the populous areas of the Boise metropolitan area, Treasure Valley and Magic Valley.-Counties:Ada |Adams |Boise |Canyon |...

 part of the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Idaho

Idaho

Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

, in Owyhee County

Owyhee County, Idaho

Owyhee County is a county located in the southwestern corner of the U.S. state of Idaho. In area it is the second largest county in Idaho, behind Idaho County. As of the 2000 Census, Owyhee County had a population of 10,644...

. Located on State Highway 51

Idaho State Highway 51

State Highway 51 is a 92 mile road in southwestern Idaho from Mountain Home south to the Nevada border, where it continues as State Route 225 to Elko. At its northern terminus in Mountain Home, SH-51 connects at the junction of U.S. Highway 20 and Interstate 84...

, it is 13 miles north of the border with Nevada

Nevada

Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...

 and 72 miles south of Mountain Home

Mountain Home, Idaho

Mountain Home is the largest city and county seat of Elmore County, Idaho. The population was 14,206 at the 2010 census. Mountain Home is the principal city of the Mountain Home, ID Micropolitan Statistical Area, which includes Elmore County....

. The community lies at the north edge of the Duck Valley Indian Reservation

Duck Valley Indian Reservation

The Duck Valley Indian Reservation was established as a homeland for members of both the Shoshone and Paiute tribes of Native Americans. It lies directly on the state line between Idaho and Nevada in the western United States...

.

In 2000, the average median household income for the ZIP Code Tabulation Area

ZIP Code Tabulation Area

ZIP Code Tabulation Areas are statistical entities developed by the United States Census Bureau for tabulating summary statistics from Census 2000. This new entity was developed to overcome the difficulties in precisely defining the land area covered by each ZIP code...

that includes Grassmere and Riddle was $30,921. Riddle's elevation is at 5,367 / 1636 (ft / m) above sea level.

At Riddle is a general store with a gas station which is run by the Riddle Ranch. The main buildings of the Riddle Ranch can be seen across the meadows to the west and north. Hwy 51 runs right through the middle of Riddle Ranch. At certain times travelers down Hwy 51 may have to stop and wait for a few minutes while Riddle Ranch buckaroos on horseback cross the highway with hundreds of cattle.