Glen Lake & the Narrows — a stop on M-22 North.
On your right through here is Glen Lake, and it is startlingly beautiful — people argue about whether it beats the big lake, and it's a real argument.
It's actually two lakes joined by a narrows: Big Glen and Little Glen, separated by a causeway the road runs across. Big Glen is deep — well over a hundred feet — and it runs an almost Caribbean turquoise over its sand bottom, which is a genuinely startling thing to come around a corner and find in northern Michigan. Little Glen is shallow and warms up fast, which is why the swimming is better there in June.
The lake exists because of the dunes. Glen Lake was once an open bay of Lake Michigan, and the sand that built Sleeping Bear gradually walled it off, trapping the water behind it. So it's a drowned bay with a sand dam.
From the top of the Dune Climb you look straight back down onto it, and that view — turquoise lake, dark green hills, and the great pale sweep of sand in between — is the one that ends up on the covers of the guidebooks.
The causeway is a good spot to pull over, and there's a small beach. Just watch the traffic; the shoulder is narrow and everybody is looking at the water rather than the road.