Carter also posted a photo of the two in front of the lush green landscape, captioning the pic, "Never a dull moment #engagementparty at home in NH."
Carter's parents hosted the occasion at their family home in New Hampshire, and Jenner's mom, Linda Thompson, was in attendance.
The 32-year-old's proud mama posted a sweet message to Instagram, writing, "Big kudos to @chimelley and Mark for the incredible engagement celebration you hosted in your fantastic New Hampshire home for these two love birds @brodyjenner & @kaitlynn_carter ! And a deeply heartfelt thank you for raising such a remarkable young woman, who has brought so much joy into Brody's and my life. You have a great family!❤️❤️ I love y'all!! #grateful."