2020 census

As of the 2020 census, there were 248 people, 135 housing units, and 104 families. The racial makeup was 218 White people, 3 African Americans, 3 Native Americans, 3 Asians, 0 Pacific Islanders, and 21 people from two or more races. 7 people were Hispanic or Latino.^[6]

The ancestry of Grays River was 14.5% English, 6.6% Irish, 3.5% German, and 2.6% Norwegian.^[6]

The median age in Grays River was 68.9 years old. 63.2% of the population were 65 or older, with 41.7% from 65 to 74 years, 8.8% from 75 to 84, and 12.7% were 85 or older.^[6]

The median household income was $54,048, families had $64,583, and non-families had $52,857. 0.0% of the population were in poverty.^[6]

2010 census

As of the census of 2010,^[3] there were 263 people, 110 households, and 83 families residing in the CDP. The population density was 13.03 people per square mile (5.03 people/km²). There were 128 housing units at an average density of 6.34 per square mile (2.45/km²). The racial makeup of the CDP was 94.3% White, 0.4% African American, 0.4% Native American, 1.1% Asian, 0.0% Pacific Islander, 1.5% from other races, and 2.3% from two or more races. Hispanic or Latino of any race were 2.7% of the population.

There were 110 households, out of which 19.1% had children under the age of 18 living with them, 68.2% were married couples living together, 6.4% had a female householder with no husband present, and 24.5% were non-families. 20.9% of all households were made up of individuals, and 13.6% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the average family size was 2.71.

In the CDP, the age distribution of the population shows 18.3% under the age of 18, 5.7% from 18 to 24, 13.3% from 25 to 44, 38.0% from 45 to 64, and 24.7% who were 65 years of age or older. The median age was 55.5 years. For every 100 females, there were 103.9 males. For every 100 females age 18 and over, there were 112.9 males.