While state requirements vary on the number of instructional days and/or hours in the school year, the majority of states require 180 days of student instruction. Most also specify the minimum length of time that constitutes an instructional day. Some states set instructional time in terms of days, some specify hours, and some provide specifications for both and may require districts to meet either or both. This report reviews the minimum number of instructional days/hours in a school year and the start dates prescribed by law, where specified. Thirty-six states and the District of Columbia allow local districts or regions to determine when the school year begins.