The model posted a photo Saturday of her in a cool looking desert-y, mountainous region with a body of water below. She called it "not earth" from a trip she took a few weeks ago -- but didn't give much more of a hint than that. It could be anywhere on its face.

Now, it appears her recent point guard boo thang might've actually spilled a major clue -- assuming he and Kendall are still hanging out as much as they were earlier this year. Devin put up a few photos himself a few days ago of him hiking at Slide Rock State Park.

It's a place with tons of canyons and with tons of creek beds covering the floor throughout -- and just looking at the photos, we have to say they look kinda similar in scenery.

Of course, Devin plays for the Phoenix Suns -- and presumably has a place out there too. So, if they are hookin' up -- like Kendall has implied of late -- it's safe to assume she was somewhere in Arizona with her guy before he was sequestered away for work.