Source: Home – MissionUS
For students, MissionUS is an opportunity to live a bit of US history, while teachers will have access to a wide range of support materials for each mission. The site asks you to read through the materials and do the mission before assigning the site as work.
The site does require students to create an account:
Even though that may be a little bit of a pain, there is nothing that says you can’t create a few accounts ahead of time. Groups could be assigned an account to allow students to complete a mission together, or, you as the teacher could lead the whole class in completing a mission.