The internet, social media, and personal devices have enabled an unprecedented spread of historical information. They have opened new avenues of public history and expanded access to historical sources and scholarship. But, online platforms also allow politicians, hobbyists, and hate groups that advance historical misinformation and disinformation to reach a far greater audience than ever before. SHEG's founder and executive director Sam Wineburg recently took to Twitter to demonstrate how historical misinformation proliferates online, and how we can practice Civic Online Reasoning to investigate online historical claims.