In Michigan, the southern part of the state is broken up into many small parcels of acreage. There are still big farms, but many have been broken into small 5 to 10 acre plots. Mostly because the "yuppies" wanted out of the city and property values were very high at one time. Trespassing in MI is a thing landowners take pretty seriously, which is why many try to anchor a deer on the spot. Properties are "normally" marked on every tree with No Trespassing signs.
The State does not post its borders, except for most corners. However the landowners generally post private property surrounding it.