Grace City is a city in Foster County, North Dakota, United States. The population was 53 at the 2020 census. Grace City was founded in 19…Grace City is a city in Foster County, North Dakota, United States. The population was 53 at the 2020 census. Grace City was founded in 1910. According to the United States Census Bureau, the city has a total area of 0.40 square miles, all land.