Drive over the clanking metal Warren Road Bridge in Cockeysville this dry autumn and you’ll see long stretches of mud rising from Loch Raven Reservoir.

A flock of Canada geese parades over the flats these days, their harsh calls echoing through the surrounding woods.

But just over a century ago, more than 900 people lived here, residents of a bustling mill town known as Warren. Generations worked in mills powered by the Gunpowder River that cranked out flour, grain, silk and cotton duck — a sturdy fabric used for sails and awnings. Children roamed barefoot, rolling hoops and shooting marbles. There was a school, two general stores, a postmaster. The bells of three churches pealed each Sunday.

But in 1921, everything was about to change.

Twenty miles south in Baltimore’s City Hall, officials were finalizing discussions with mill owner Summerfield Baldwin to purchase the town of Warren and cart away stones, beams and even graves.

Then the waters of the Gunpowder — already pressing against the newly enlarged Loch Raven dam — would be allowed to rush in and cover the remains of the little town.

The town’s 900 residents had weathered many trials, said Sally Riley, a Baltimore County Historical Society volunteer who has given many presentations on Warren’s history. Fires. Strong storms. A brutal outbreak of the Spanish flu.

“The town was victim to a number of catastrophes,” Riley said.

In the end, Warren was vanquished by thirst.

Baltimoreans drank water from the Jones Falls in the early 1800s, but they also fouled the water with sewage and factory waste, leading to outbreaks of yellow fever and cholera.

Baltimore officials dammed the Gunpowder near Towson in the 1870s to create a reservoir of clean drinking water. But by the time the Great Baltimore Fire decimated downtown Baltimore in 1904, it was clear that the city and surrounding county needed an additional source of water, both to drink and to fight fires.

Baldwin struck a secret deal with City Hall in 1908 to sell Warren and Phoenix, where he also owned a mill. When The Baltimore Sun uncovered the deal, outrage ensued, touching off years of negotiations. Baldwin ultimately sold the parcels of land for $1 million, about $18 million in today’s money.

In December 1921, a Baltimore Sun reporter wandered around Warren to describe the town before it vanished.

“The church bells were there yesterday, the schools, the cozy houses, children running about the roads and thinking of Christmas, garments freezing stiff on the clothes lines,” the reporter wrote.

Two months later, the mills ceased production. Some residents moved to the area of Cockeysville known as Texas. Others relocated to work in cotton duck mills in Woodberry or the newly opened Sparrows Point steel mill, Riley said.

Meanwhile, workers deconstructed Warren, taking apart the mills, homes, general stores, churches and school, leaving only the foundations of buildings and a single flagpole. A few houses were moved about a mile away, to a neighborhood now near the Cockeysville Senior Center. Graves were dug up and bodies reinterred at other cemeteries, including that at nearby Poplar Grove United Methodist Church.

Then the dam was opened and the water flowed in, covering the village.

Over the next two decades, the flagpole would occasionally appear when water levels dipped. During a lengthy 1941 drought, the Sun reported that stone fences and foundations were emerging from the mud in a story headlined “Ghost Town Returns to View.”

But over time, many forgot that Warren had even existed.

Poet Ann Eichler Kolakowski was helping her grandmother move into an assisted living facility in 2002 when she came across a faded notebook labeled “Warren School.”

Although she had grown up nearby, Kolakowski had never heard of Warren, where her grandmother had spent her formative years. Kolakowski grew fascinated by the town and pored over records, documents, photos and oral histories compiled by John McGrain, then the county’s chief historian.

“It broke my heart to find out it had been erased,” she said. “And it had been my family’s home.”

Kolakowski wrote an article about Warren for Style magazine in 2005 and was invited to bring her grandmother, Florence Marian Brown Eichler, to Warren Elementary that year, where a group of fifth-graders shared their research on the little town whose name lives on in their school. Ghostly black-and-white photos from the town still hang in the school’s lobby.

Eichler died the following year at age 103. She is believed to have been the last surviving resident of Warren.

Kolakowski was inspired to write a book of poems about Warren, most in the voices of real residents, such as Mary Underwood, whose young son died in a wagon accident, and Sarah Howard, who was forced to work 10-and-a-half-hour days in the mill as a child.

The final poem, “On Warren Road Bridge,” laments that no sign commemorates Warren.

“There was a town here once,” writes Kolakowski. “And then there wasn’t.”