Even though it celebrates its 250th birthday this year, the Fort Pitt Block House’s age isn’t the most impressive thing about it.

Certainly, the fact that it has survived two-and-a-half centuries is remarkable, but it’s done more than that—it’s survived two-and-a-half centuries at one of the continent’s most important strategic locations through war, industrialization, rapid growth and crippling decline.

“It’s a complex story that has these three phases: the military phase, the residential phase and a historical site phase,” says Maureen Mahoney Hill, a spokesperson for the Block House.

After passing from British to colonial control, the fort was no longer in military use by 1779. It served for a while as a trading post until 1784, when Major Isaac Craig—of Craig Street fame—purchased what is now a large section of the Point and re-purposed the former fortification.

“Shortly after it was decommissioned, Craig used it as a private residence,” Hill says. “He built a building around it but lived in the Block House.”

Though it had various owners until it found its way into Mary Schenley’s substantial land portfolio, people continued living in the Block House until 1894. Through much of that time, the Point was a slum and the old redoubt was one of its awkward, little houses. One of the building’s last tenants was an old Irish woman named Sibby Powers, who not lived on the first floor but attained popularity among neighborhood children for operating a candy store out of her front window.

“It became tenement housing as the Point became blighted,” Hill says. “There were still two families living there when the Daughters of the American Revolution wrote to Mary Schenley and asked her to donate it.”

Schenley, who also donated the expanse of land for the Pittsburgh park which now bears her name, acquiesced, and the DAR set about restoring it and turning it into an historical site and museum.

Eight years later, Henry Clay Frick, who had by then purchased all of the land around the Block House, stepped in. Aiming to take over the center of America’s most bustling industrial city, he wanted the building moved or torn down to make way for a railroad extension and a series of warehouses.

Frick offered the DAR $25,000 to remove the Block House from the Point and relocate it to Schenley Park, but was rebuffed. Following a series of legal battles during which both public and private interests tried to seize the land through eminent domain, the women of the DAR prevailed, and the Block House remains the oldest structure in America west of the Allegheny Mountains and a substantial marker of the American frontier.

Now, the Block House will celebrate 250 years with a full slate of outdoor programs in Point State Park on August 9. Activities will run from 11 a.m. to 4 p.m. and include firings of an 18th century cannon, a pipe and drum corps and reduced-price admission to the Fort Pitt Museum. For a full schedule of events, see the Block House 250 website.

Admission to the Block House itself is and will remain free and open to the public.

“And it’s really all owed to this group of women who, back then, couldn’t even vote,” Hill says.