Traveling to and from New York by land in the 1700s was not for the faint of heart. The city of about 18,000 people was generally huddled around or below Wall Street, and the few roads that ran north through the wilds of Manhattan were primitive and hazardous.

To help guide hearty travelers by foot, horseback, and stagecoach, city officials installed a series of stone mile markers on the Old Post Road that let people know how far they were from city hall.

The Old Post Road, or King's Highway, as it was known before the Revolutionary War, followed a preexisting Native American trail into today's Westchester and then up to Albany or Boston. As its name indicates, the road was used for mail delivery, and Postmaster Benjamin Franklin himself supervised the placing of the mile markers.

Over the years, the mile markers—the first at Rivington Street and the Bowery, and the last in the Bronx near Spuyten Duyvil, according to a 1915 document from the City History Club—disappeared from the streetscape.

Yet one of these "battered and broken milestones," as an 1895 Sun article put it, still exists today in Upper Manhattan. Amazingly, it's embedded in a stone retaining wall just steps from Broadway and 213th Street.

The milestone, which used to tell travelers that they were 12 miles from the main city, has been part of this stone wall (photo, about 1910) since the end of the 19th century.

How did it end up here? Well, this wasn't the milestone's original exact location. According to the Sun, it used to stand on a nearby road called Hawthorne Street, which is the former name of 204th Street.

When construction crews were building roads and otherwise modernizing Inwood, they came across the mile marker that had outlived its purpose. William Isham, a wealthy leather merchant and banker with a nearby estate and mansion (above), took the mile marker and had it embedded into the wall.

"Mr. Isham had the stone marker moved and installed in the wall next to his gate when it was tossed aside by road workers on Broadway," explains NYC Parks.

"When roadway workers were removing a red sandstone mile marker, William Isham had it installed at the right side of his entrance gate on Broadway," echoed the Historic Districts Council.

After Isham's death, his family donated the land from his estate, including the retaining wall with the mile marker, to the city in 1911 to create Isham Park.

Sadly the 12-mile marker has lost its inscription. But it's still an amazing remnant of the early days of Gotham, when getting far out of the main part of town could be treacherous and disorienting.

Though it's the only milestone technically on a Manhattan street, there's at least one other Old Post Road mile marker preserved in Manhattan: the 11-mile marker. It's on the grounds of the Morris-Jumel Mansion on 160th Street near St. Nicholas Avenue and is noted with a small plaque.

Brooklyn, on the other hand, has its own mile marker relic still visible on a street. (Or at least it was several years back.) A stub of granite with the number 3 carved into it is on Ocean Parkway and Avenue P. That's 3 as in three miles to Prospect Park, where Ocean Parkway begins.

[Top image: Wikipedia; second image: New-York Historical Society; third image: NYC Parks via Volunteers for Isham Park; fourth image: Wikipedia]