Highmore is a city in and county seat of Hyde County, South Dakota, United States. The population was 795 at the 2010 census.
A post office called Highmore has been in operation since 1882. The city was named from its lofty elevation.
Highmore is located at 44°31′7″N 99°26′28″W (44.518700, -99.441106).
According to the United States Census Bureau, the city has a total area of 1.89 square miles (4.90 km2), all of it land.
Highmore has been assigned the ZIP code 57345 and the FIPS place code 28960.
As of the census of 2010, there were 795 people, 347 households, and 201 families residing in the city. The population density was 420.6 inhabitants per square mile (162.4/km2). There were 393 housing units at an average density of 207.9 per square mile (80.3/km2). The racial makeup of the city was 91.7% White, 6.5% Native American, 0.1% Asian, 0.4% from other races, and 1.3% from two or more races. Hispanic or Latino of any race were 1.9% of the population.
There were 347 households, of which 24.8% had children under the age of 18 living with them, 47.3% were married couples living together, 6.9% had a female householder with no husband present, 3.7% had a male householder with no wife present, and 42.1% were non-families. 39.8% of all households were made up of individuals, and 20.5% had someone living alone who was 65 years of age or older.