ST. MARY'S CITY -- For about 6 1/2 hours yesterday, John Mackall Brome's 150-year-old plantation house became Maryland's biggest mobile home.
The 120-ton, 85-foot-long frame mansion was jacked up on steel beams, mounted on aircraft tires and hauled down Route 5.
After a right turn through a series of hayfields and hedgerows, the house came to a stop at a new state-owned site on the St. Mary's River, about a mile from the spot that Dr. Brome chose in 1840.
Historic St. Mary's City -- the state agency that is the caretaker of Maryland's 17th-century Colonial capital -- ordered the $220,000 move as part of its mission to uncover and develop the remains of the vanished town.
"I think personally they're doing the right thing," said Thomas Howard, 72, great-grandson of John Mackall Brome. He and his wife sold the property to the state and were its last private occupants. His mother, Jeanette Howard, was born a Brome.
"I wouldn't want to see it torn down," Mr. Howard said as he watched the house roll past him on Route 5.
"There are too many nice memories. We had a lot of good times there."
One of the memories hauled down the highway inside the mansion was a piano dating from the 1860s. Mr. Howard said the piano, which his family left to the state, still has damage to its ivory keys inflicted by Union soldiers who stormed through during the Civil War.
Four outbuildings that served the old tobacco plantation were also moved. They included a duplex slave quarters with a dirt floor that St. Mary's City officials said housed tenants until the 1960s. Archaeology turned up a large quantity of printers' lead type beneath the dirt floor, indicating the site had earlier belonged to the Nuthead print shop, Maryland's first.
State archaeologists discovered years ago that the Brome-Howard House stood where Maryland's first governor, Leonard Calvert, built his house in 1635.
In 1645, the Catholic capital was captured and sacked by forces loyal to the English Parliament. The troops dug a moat around the house and built earthworks and a palisade, turning the place into the only English Civil War fort on the continent.
In the mid-1980s, during work to replace the Brome-Howard House's septic tank, archaeologists discovered traces of the earthworks and moat, which had been used as a trash dump.
"We were finding a lot of 17th-century artifacts, including pieces of armor and shot," said Joseph Anderson, acting director of Historic St. Mary's City. "The site also had been used by Native Americans. It has been continuously occupied for 10,000 years."
Despite the cold and intermittent drizzle, yesterday's move drew dozens of curious onlookers, some with cameras, some unable to continue their journeys for 75 minutes while the house blocked the road.
The mansion wasn't the biggest thing that Jim, John, Joe and Jerry Matyiko have ever moved. The four Matyiko brothers from Sharptown operate Expert House Movers of Maryland, and last year they moved a 2,000-ton stone and brick lighthouse on Block Island, R.I.
But this job required that they not only move the house without damage but do it without crushing artifacts just beneath the soil around it. "The main thing was to protect the archaeological site," said Jerry Matyiko, 46.
The three-story house, with a two-story addition and one-story attached kitchen, had to be jacked up and supported by steel beams. The fear was that the move might damage rotted sills, crack the plaster or break windows.
"The whole building came up without anything separating," he said. "There's not even a paint crack."
By 10 a.m. yesterday, the house had been rolled onto the highway, supported by 32 tanker aircraft tires placed in four groups to spread the weight. Led by a state police car, it was hauled south by a rubber-treaded mini-tank and a bulldozer.
Utility crews took down power and telephone lines that stretched across the way, then quickly strung them up again.
The front and rear porches cleared power lines on each side by a foot or two and brushed an occasional tree branch.
Remi Sonneville, a bridge inspector hired by the state, stood by to ensure the house didn't damage the highway or culverts along the way.
"It's not the gross weight that's critical," he said. "It's how it's spread on the roadway."
At 4:15 p.m., the movers rolled the house down a dirt ramp onto a cellar hole that will be enclosed later with a foundation. It all went "perfectly," said Mr. Anderson. "Couldn't have gone better."
The state has no immediate plans for the Brome-Howard house, but converting it into a bed and breakfast is one option being considered.