Hastings is a city and the county seat of Adams County, Nebraska, United States. The population was 25,152 at the 2020 census, making it the …Hastings is a city and the county seat of Adams County, Nebraska, United States. The population was 25,152 at the 2020 census, making it the 8th most populous city in Nebraska. Edwin Perkins invented Kool-Aid in Hastings in 1927; the town celebrates the invention with the Kool-Aid Days festival every August.