The tiny Little Giant Creek drains a few swamps north of Marenisco and flows over to the scenic Presque Isle River. In these swamps there was once a small waterfall over a bump of rock. Over the years the creek has diverted around the rock to form a small muddy channel between two deep pools. Signs of the waterfall are obvious - but it is no longer here.
An overgrown and muddy two-track leads north of US-2 and provides access to the land around Little Giant Falls. This track is not marked and is somewhat hard to find. It is 1.1 miles east of Presque Isle River bridge and .7 miles west of M-64. You can park a few yards into the track, though there is too many downed trees and ruts to drive too far off the highway.
From here it's a tough walk north. The easiest way to find the falls without a GPS is to follow the track north and then head left with the powerlines about .5 miles in. Follow the lines for .5 miles and eventually cut to the right, trying to skirt the edge of the swamp. The creek will bend to you and you can follow it upstream to the 'falls'.
Otherwise you can continue on the track past the powerlines, staying on it for about .75, before cutting to the left towards the falls. This is difficult to do without a GPS, as the woods are surprisingly thick and rugged. Either way there isn't too much danger of getting lost - the creek, the track, and two powerline routes form a box that is no more than a square mile in size.