This is a food park now with a stone monument stating the original location of the sugar mill. If you put sugar mill into your mobile App, it'll probably take you to the large former sugar mill which is now a zipline place. If you visit this island - you won't get a lot of help with directions. The place is right across from the main drag in town with all the shops. You should be able to see a few food trucks and that'll mark your spot.

The Koloa sugar monument is the stone remnants of an old sugar mill. There is a plaque documenting the history of the area, but otherwise there is nothing else to see. You can essentially see everything just by driving by. Unfortunately, this place is basically just a spot for food trucks to park and sell their stuff.