Ken Aderholt didn’t realize he lived in a river until federal bureaucrats told him so. It was surprising for a man whose family had lived in the house for generations without it ever floating away or even flooding. But the Bureau of Land Management has decided that the Red River of North Texas is a peculiar one—covered by by old growth trees and grazed by deer and cattle, low on catfish but high in cactus. Never mind that the nearest water flows almost a mile away.

Unfortunately for Mr. Aderholt and countless others that live along the Red River, the federal government’s decision to redefine “river” to include dry uplands means they could lose their homes and ranches. The effect of the redefinition is to move the border of Texas far to the south, transferring thousands of acres of property from Texan ranchers to the government.

The federal government owns a thin strip of land between Oklahoma and Texas—from the middle of the Red River to its southern bank. Oklahoma’s territory includes only the northern half of the river, and Texas begins at the southern bank. This was established by the Supreme Court in a series of cases culminating in a 1923 decision defining the “boundary bank.”

In 2008 the BLM began claiming that the high bluffs that make up the edge of the river valley are the “banks” of the river. That definition of “bank” would make the river several miles wide, causing it to be simultaneously the world’s largest and driest river. The BLM seems determined to show it has no more respect for the English language than it does for property rights.

The Supreme Court was clear that the legal definition of “river bank” matches the ordinary English usage of the term. The bank is what separates the sandy riverbed from the vegetation-covered uplands: “On the valley side of the bank is vegetation and on the river side bare sand.”

Yet the BLM has placed survey markers in some places a mile from the river, in areas covered by ancient oaks and ranch houses, all the while claiming it is using the Supreme Court’s 1923 definition of “bank.”

That cannot be. As the casual observer probably knows, and as the Supreme Court specifically stated, large trees and other vegetation do not grow in riverbeds.

Thus, the federal government expands its thin strip of barren sand to include homes and thousands of acres of productive farmland, all without any legislative action or even a definition of “bank” capable of holding water. It gets worse.

Whereas law-abiding bureaucrats would have backed down when they realized they were out of their depth, the BLM decided to muddy the waters further.

It will not say precisely which land it claims to own, only noting that it is probably no more than 90,000 acres. When North Texas landowners questioned BLM officials at a recent meeting in Fort Worth, the officials declined to give any specifics and instead suggested the landowners get a lawyer if they don’t like the BLM’s actions.

And so they did.

We at the Texas Public Policy Foundation’s Center for the American Future are suing to stop the land grab.

Texas ranchers have already led the BLM to water. Hopefully the court can make them think.

Joel Stonedale is an attorney with the Center for the American Future at the Texas Public Policy Foundation.