I just finished the Simpsons season 14 episode “Barting Over” (Bart moves out when he learns that he was the spokesbaby of a commercial, which Homer spent the money away for himself), which was originally the 300th episode but it was actually 302 with “Strong Arms of the Ma” (Marge gets mugged outside a Kwik-E-Mart and starts working out and ends up taking steroids). This was referenced in the aforementioned episode when Lisa has a counter of 300 (stupid things Homer’s done) and Marge thought it was 302.
Technically it’s 301, since “Stark Raving Dad” still isn’t on Disney+, or anywhere else non-DVD based for that matter.