there are Townships and Ranges that act as latitude and longitude. where they meet are 36 squared miles called “Sections”, i.e. Township 7 South, Range 2 East.

inside T7s-R2e there are 36 sections, each a mile square (640 acres, more or less). let’s pick one, say Section 5 of Township 7 South, Range 2 East in such and such County.

Section 5 (7s-2e) has 4 quarters, just as each other section does. The 4 quarters, Northwest (NW/4), Northeast (NE/4), Southwest (SW/4), and Southeast(SE/4) each contain 160 acres, which can each be broken down into 4 quarters of 40 acres, and so on….

so the Southeast Quarter of the Northwest Quarter of the Northwest Quarter of Section 5, Township 7 South, Range 2 East, contains 10 acres. and easier way to write it would be the SE/4 NW/4 NW/4 Sec. 5 (7s-2e).

also, the NE/4 and the NW/4 make up the North Half (N/2); the SW/4 and SE/4 make up the S/2.

Some states use the Metes and Bounds method, which is just fucking nuts.

maps.google.com/maps?ll=37.873363,-99.229374&spn=0.095259,0.154324