Is your family ready to embrace a four-day school week? Although it's a fairly new concept, two school districts in Northern Michigan have already adopted it. According to the Associated Press, there are roughly 13,000 school districts in the United States. Two decades ago, there were only about 100 school districts in the US observing a four-day week. That number grew to 662 in 2019 and currently stands at close to 900 districts nationwide.