Grain Valley is a city in Jackson County, Missouri, United States. Grain Valley is located in the Kansas City Metropolitan Area and is a suburb of Kansas City. The population was 12,854 at the 2010 census and an estimated 14,526 in 2019. It is 23 miles (37 km) east of downtown Kansas City.
Grain Valley was founded in the 1870s. The city was named for the general character of the grain-producing region. A post office called Grain Valley has been in operation since 1879.
Grain Valley is located at 39°0′31″N 94°12′27″W (39.008733, -94.207465).
According to the United States Census Bureau, the city has a total area of 6.07 square miles (15.72 km2), of which 6.06 square miles (15.70 km2) is land and 0.01 square miles (0.03 km2) is water.
At the 2010 census there were 12,854 people in 4,566 households, including 3,395 families, in the city. The population density was 2,121.1 inhabitants per square mile (819.0/km2). There were 4,867 housing units at an average density of 803.1 per square mile (310.1/km2). The racial makeup of the city was 92.6% White, 2.5% African American, 0.6% Native American, 0.6% Asian, 0.1% Pacific Islander, 1.2% from other races, and 2.3% from two or more races.