This research methods article introduces the open source PERSUADE 2.0 corpus. The PERSUADE 2.0 corpus comprises over 25,000 argumentative essays produced by 6th-12th grade students in the United States for 15 prompts on two writing tasks: independent and source-based writing. The PERSUADE 2.0 corpus also provides detailed individual and demographic information for each writer. The goal of the PERSUADE 2.0 corpus is to advance research into relationships between discourse elements, their effectiveness, writing quality, writing tasks and prompts, and demographic and individual differences.