I will be honest and tell you that this was our hesitation when choosing Peddie over a more prestigious school a few years ago. What I have learned since is that Peddie does itself a disservice by not marketing their Humanities department enough.
The quality of both English and History teachers is outstanding, as is the variety of classes and electives. All focus on the development of critical thought and skilled writing.
The kids are engaged and discussions are rich. Everyone I know reports being very well prepared for college writing. Most importantly, I have seen students guided by faculty to discover new passions in these areas time and time again.
Like in STEM there are signature experiencial programs in Arts, Creative Writing. and Languages. There is also the opportunity to design your own, which History minded students often do.
Each year Peddie students receive a number of Scholastic awards for their visual and written work. This included 3 (if I remember correctly) national medals last year.
I hope this helps. Feel free to DM me if you would like - I’m happy to share more of our experience.