I've linked the AP report that MLK's event was "more than 200,000 people".

Also linked is Newsweek's Exclusive sit down w/FBI & SS "as many as 120,000 show up on the Mall on January 6, according to classified numbers still not released by the Secret Service and the FBI but seen by Newsweek.

In addition, there were 3 other permits (Ellipse, Freedom Plaza & Sylvan theater) totally 75,000 just for permitted rally goers "but it swelled to much more. " That brings the J6 crowd to 195,000 not including the "swelled to much more" estimates.

https://www.newsweek.com/exclusive-classified-documents-reveal-number-january-6-protestors-1661296

https://apnews.com/article/march-washington-1963-martin-luther-king-6e4aa7bb8cdbcafd09218557cc0ea842