According to the United States Census Bureau, the CDP has a total area of 20.0 km² (7.7 mi²), all land.
Morongo Valley lies along the western edge of the Mojave Desert, and as such is generally dry. Monsoonal moisture leads to thunderstorms at times during the summer, but in the winter, Pacific storms bring most of the rain.
As of the census of 2000, there were 1,929 people, 811 households, and 473 families residing in the CDP. The population density was 96.4/km² (249.5/mi²). There were 960 housing units at an average density of 48.0/km² (124.2/mi²). The racial makeup of the CDP was 91.86% White, 0.83% African American, 1.40% Native American, 0.36% Asian, 0.10% Pacific Islander, 3.37% from other races, and 2.07% from two or more races. Hispanic or Latino of any race were 9.33% of the population.
There were 811 households out of which 26.5% had children under the age of 18 living with them, 43.9% were married couples living together, 10.2% had a female householder with no husband present, and 41.6% were non-families. 33.7% of all households were made up of individuals and 11.8% had someone living alone who was 65 years of age or older. The average household size was 2.37 and the average family size was 3.04.
In the CDP the population was spread out with 25.2% under the age of 18, 6.3% from 18 to 24, 25.6% from 25 to 44, 27.8% from 45 to 64, and 15.1% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 100.1 males. For every 100 females age 18 and over, there were 101.3 males.
The median income for a household in the CDP was $36,357, and the median income for a family was $36,643. Males had a median income of $37,091 versus $26,528 for females. The per capita income for the CDP was $19,624. About 12.2% of families and 19.4% of the population were below the poverty line, including 28.7% of those under age 18 and 19.0% of those age 65 or over.
Morongo Valley is unincorporated, and is under the jurisdiction of San Bernardino County. The main commercial development of Morongo Valley lies along Highway 62. A popular destination in Morongo Valley is the Big Morongo Canyon Preserve, where one can take hikes, go bird-watching or stroll along the walkways. The governing body of Morongo Valley is the Community Services District (CSD), which has five board members. The only school in Morongo Valley is Morongo Valley Elementary School (MVES), which is part of the Morongo Unified School District. MVES has an enrollment of a few hundred students.
In the state legislature Morongo Valley is located in the 18th Senate District, represented by Republican Roy Ashburn, and in the 65th Assembly District, represented by Republican Paul Cook. Federally, Morongo Valley is located in California's 41st congressional district, which has a Cook PVI of R +9 and is represented by Republican Jerry Lewis.Paradise Fire
In June 2005, a fire started on Paradise Avenue in western Morongo Valley. This fire quickly spread, torching about six thousand acres (24 km²). Luckily, only seven homes were burned. The fire also damaged some of the walkways in the Big Morongo Canyon Preserve, but all damage has been repaired and the entire preserve is once again open for birding and hiking.
In July 2006, a fire started by dry lightning in Yucca Valley was almost 100 percent contained, however due to extremely low humidity, high temperatures, and 40 mile per hour gusts, the fire grew. The fire quickly spread from Yucca Valley through Pioneertown and Big Morongo. In fact, another small fire dubbed the Millard Complex fire merged with the Sawtooth Complex fire. Well over a hundred structures were burned in the two fires.