Shelby County, IL Water Table Trend
Shelby County, IL: the closest actual trend
The closest qualifying well to Shelby County is 34 miles away in Macon County, IL, where the trend runs declining, slower than most declining counties.
Shelby County itself has no monitoring well with enough history to call its own trend, so treat this as a regional estimate, not Shelby 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 Macon 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.
Shelby County, Illinois in brief
About 20,542 people live across Shelby County's 759 square miles, in Illinois. USGS's National Groundwater Monitoring Network covers 1,449 of 3,222 US counties (45%) today; Shelby County isn't one of them yet, see the methodology guide for the exact qualifying bar.