Williamson County, IL Water Table Trend
Williamson County, IL: the closest actual trend
The closest qualifying well to Williamson County is 21 miles away in Saline County, IL, where the trend runs holding roughly steady.
Williamson County itself has no monitoring well with enough history to call its own trend, so treat this as a regional estimate, not Williamson County's own number. If you own a well here, comparing your own depth log against this regional figure is worth doing before assuming either way. See Saline County, IL's full page. See the no-data guide for why a county this close to a qualifying well still doesn't get its own number.
Williamson County, Illinois in brief
About 67,064 people live across Williamson County's 420 square miles, in Illinois. USGS's National Groundwater Monitoring Network covers 1,449 of 3,222 US counties (45%) today; Williamson County isn't one of them yet, see the methodology guide for the exact qualifying bar.