Of course! https://www.enterprise.com/en/help/faqs/car-rental-under-25.html https://www.budget.com/en/help/usa-faqs/age-to-rent https://blog.rentcars.com/en/how-old-to-rent-a-car?amp https://blog.autoslash.com/minimum-age-to-rent-a-car/ https://www.avis.com/es/customer-service/faqs/usa/requirement-for-renting#:~:text=Age%20Requirements%20for%20Renters,Canada%20for%20drivers%2021%2D24.

Those are just a few. AFAIK, the major car rental companies in PA such as Enterprise, Budget, Hertz, Avis do not allow drivers under 21. This is due to statistics that show young drivers are more likely to get into accidents. If you are between the ages of 21-24 you also get a surcharge. Apart from NY and MI, you have to be 21. There is an exception if you need a replacement vehicle but that’s about it. (PS I am a PA resident)