The population of Beaver County, Oklahoma, is 5,315 and deeply divided. In a vote last year to determine whether alcohol sales should be made legal—it’s been a dry county for more than a century—the wets initially prevailed, voting in legal liquor by a scant five votes. Then the provisional ballots appeared to tip it back to dry by a few votes. In the end, Beaver County went wet…by four votes. With the drawn-out election, it became the last county in Oklahoma where you couldn’t buy a legal drink.

Oklahoma has long been a laboratory for Prohibition—it effectively ended liquor sales in 1908, a decade before the national ban, and didn’t allow much in the way of hard liquor sales until 1959. But the most interesting result of this last electoral experiment was that, along with Beaver County, 13 other Oklahoma counties in the same election all voted to go wet.

“Dry counties” exist as a sort feral anachronism—like phone booths and video stores. They appeared in response to perceived social or economic need, and when those needs dissipated, they were left behind, like flotsam from a flood nobody remembers. We are a nation that’s pretty good at building laws, and pretty lousy at dismantling them.

And so dry counties persist—today an estimated 18 million people are unable to buy a legal drink where they live. Mostly these persist in the south, and a map of dry counties overlaid with one of the Bible Belt, not surprisingly, shows considerable overlap. (Although the penchant for dryness fades as you get closer to the Gulf of Mexico.) The states with the most dry counties are Kentucky, Arkansas and Tennessee. Fact: you can still get arrested for possession of alcohol in some dry counties, as a 69-year-old man in Culliman, Alabama, learned recently.

A survey of dry counties is complicated by the fact that there’s considerable variation in laws about what sort of sales are allowed (for instance, near-beer and wine only), and where sales can take place (bars and restaurants, grocery stores). All this confusion dates back to Repeal—once the U.S. Congress lifted the ban on liquor sales in 1933, it was left up to each state to decide if it wanted to outlaw liquor.

Many did—Mississippi, for instance, maintained its liquor ban until 1966. At least in theory—booze was still widely sold and consumed in Mississippi. Even the governor was caught up in a liquor raid while dining at a country club. A short time later, he admitted that the poorly enforced ban made his state a laughingstock, so he signed a new law that permitted the resumption of legal alcohol sales.

But the 1966 loosening of laws in Mississippi came with a catch—the state technically remained dry by default. Counties were allowed to vote whether they wanted to go wet. If they didn’t, they automatically remained dry. Today, 32 of the state’s 82 counties still prohibit liquor sales.

Kicking the can down the road from the feds to more ever-more local jurisdictions led to this fragmented process of regulating liquor. For instance, Mississippi, Tennessee and Kansas are technically dry, but allow local communities to vote to go wet. Other states have done the inverse—gone wet stateside, but permit local jurisdictions to vote whether they’d like to remain alcohol free. (More than a dozen states explicitly prohibit counties from voting to go dry even if they so choose.)

State oversight can lead to an even more curious patchwork. In some jurisdictions, cities or towns within a dry county have voted to go wet, yielding what are often called “moist” counties. For instance, Hollywood, Prineville, Reform, and Rogersville are all wet cities within dry Alabama counties.

And politics can lead to even narrower slices of wet. Moore County, Tennessee—home to the Jack Daniel’s distillery—is dry, but the distillery is allowed to sell “commemorative” bottles… that happen to be full of whiskey, provided the purchasers leave the county before consuming them.

While social currents are squirrely, dry counties have faced an ebb tide lately. Oklahoma’s sweeping vote last year—yielding 14 new wet counties—is not an outlier. About four dozen cities in Texas have petitioned to vote wet/dry in the past two years; all those that have come up for vote have gone wet. Indeed, in 1965, Texas had 142 dry counties; only five now remain.

Others are striving to go wet, if not quite succeeding. Five years ago a ballot measure in Arkansas to legalize liquor sales in all 75 counties went down to defeat. And this year a push to allow individual cities within dry counties in Arkansas to sell liquor was withdrawn, with the bill’s sponsor admitting, “I didn’t have the will of the people on this one.”

Notably, Virginia recently aimed to switch up oversight. A bill was sent to the governor’s desk earlier this year that would instantly make liquor sales legal in all counties—although the 31 dry counties could vote to remain dry (only nine are entirely dry; others are “moist”). Rather than putting the burden on the wets to lobby for sales, this approach flips the stakes such that proponents of prohibition have to take the first steps to maintain the status quo.

Why is dry America getting damp? Part of it may be the fading of collective memory—we forget why these patchwork laws were implemented in the first place. Part of it is a loosening of social mores. But a major driver is certainly practicality. Counties that forego liquor sales often lose out on economic development and retail opportunities to neighboring counties where liquor is sold. Wal-Mart in particular has been a quiet player, reportedly letting counties know that liquor sales may be a factor in whether they erect a new store within their bounds, or twenty miles down the road in a wet county. And restaurateurs, who often depend on sweetening their pot through liquor sales, may seek to put down roots in wetter terrain. As a result, potential new residents may prefer to live somewhere that there’s more choice in their dining options

Studies also suggest, paradoxically, that dry counties may actually be more troubled by drunk driving. The reason isn’t all that hard to figure out: those who choose to patronize a bar will have to drive longer distances to cross a county line. (Other studies have found that many liquor stores set up just over the county line for convenience to the drys.) A 1997 study in Texas, found the rate of fatalities in drunk-driving accidents was three times higher in dry counties than in wet.

Evidence is mounting that the era of dry counties is in eclipse—although how fast it fades into oblivion is yet to be known. But it’s clear that a century after it implementation, Prohibition is—at last—loosening its long grip.

Wet, it appears, is our natural condition. Dry is not.