The first known mention of a “Conestoga wagon” was by Ben Garcia on December 31, 1717 in his accounting log after purchasing it from James Hendricks.  It was named after the “Conestoga River” or “Conestoga Township” in Lancaster County, Pennsylvania, and thought to have been introduced by Mennonite German settlers. 
In colonial times the Conestoga wagon was popular for migration southward through the Great Appalachian Valley along the Great Wagon Road. After the American Revolution it was used to open up commerce to Pittsburgh and Ohio. In 1820 rates charged were roughly one dollar per 100 pounds per 100 miles, with speeds about 15 miles (25 km) per day. The Conestoga, often in long wagon trains, was the primary overland cargo vehicle over the Appalachians until the development of the railroad. The wagon was pulled by a team of up to eight horses or up to a dozen oxen. For this purpose, the Conestoga horse, a special breed of medium to heavy draft horses, was developed.
The Conestoga wagon was cleverly built. Its floor curved upward to prevent the contents from tipping and shifting. The average Conestoga wagon was 18 feet long, 11 feet high, and 4 feet in width. It could carry up to 12,000 pounds of cargo. The cracks in the body of the wagon were stuffed with tar to protect them from leaking while crossing rivers. Also for protection against bad weather, stretched across the wagon was a tough, white canvas cover. The frame and suspension were made of wood, while the wheels were often iron-rimmed for greater durability. Water barrels built on the side of the wagon held water, and toolboxes held tools needed for repair on the wagon. Also, the feedbox on the back of the wagon was used to feed the horses. The Conestoga wagon was used for many types of travel including passage to California during the California Gold Rush.
The term “Conestoga wagon” refers specifically to this type of vehicle; it is not a generic term for “covered wagon“. The wagons used in the westward expansion of the United States were, for the most part, ordinary farm wagons fitted with canvas covers.
Text Below taken from – http://explorepahistory.com/hmarker.php?markerId=1-A-60
Throughout colonial America, overland transportation depended upon dirt roads, many of them narrow, muddy, rutted, and littered with rocks, branches, and old stumps. Soon after Pennsylvania’s establishment as a colony, the great bounty of the land presented settlers with the challenge of moving their crops and goods to market and of getting city-made goods shipped out to them. The solution was developed in the Conestoga region of Lancaster County. There, the simple colonial farm wagon was transformed into the Conestoga wagon; an elegantly designed and rugged overland freight hauler.
The first recorded use of the name dates back to December 31, 1717, when James Logan, William Penn’s former secretary, carefully recorded in his account book that he bought a “Conestogoe Waggon” from James Hendricks. Logan needed the special wagon to bring loads of furs from his trading post on the Lancaster frontier to the city and to carry a wide variety of goods back to “Conestogoe.”
The name came from area along the Conestoga River in Lancaster County, where Pennsylvania German and Swiss wagon builders created the large sturdy wagons needed to ship farm products the sixty-four mile journey to market in Philadelphia. A product of several influences, the wagon took shape over time.
To prevent cargo from shifting as the wagon bounced along rough roads, wagon-makers replaced the flat-bed of the farm wagon with a center-sloping bed. To haul large loads, they extended the bed size to thirteen to sixteen feet, expanded the width and depth to four feet, and added a white canvas, hemp, or linen cover stretched across large wooden bows to protect freight from the weather. They made axles from tough hickory and the hubs from sour gum to withstand the pounding of rough roads and enlarged the wheels to improve the ride and to ford streams and rivers and keep the cargo dry. Blacksmiths forged iron wheel rims, as well as ornate hinges, brake shafts, linchpins, hooks, staples, latches, and other fancy ironwork. To pull the heavy wagons over long distances, Lancaster County breeders provided strong, heavy horses that exhibited great stamina.
Critical to colonial commerce, Conestoga wagons were also essential to long-distance military campaigns. On April 26, 1755, Benjamin Franklin advertised for 150 wagons to serve General Edward Braddock in his upcoming campaign against the French. That summer Conestoga drivers from southern Pennsylvania responded, transporting provisions for the expedition that ended in Braddock’s disastrous defeat at Fort Duquesne.
During the American Revolution, Conestoga wagons carried supplies for the Continental Army. In the spring of 1778, one such wagon carried $600,000 worth of silver coins – a loan from the French government to the fledgling United States – from Portsmouth, New Hampshire to the nation’s treasury, which was then located in York, Pennsylvania. During the War of 1812, a large convoy of Conestoga wagons carried urgently needed gunpowder from the DuPont gunpowder works at Wilmington, Delaware to supply Commodore Perry on Lake Erie.
With the opening of the Philadelphia and Lancaster Turnpike in the 1790s and National Road in the 1810s, Conestoga wagons became the “big rigs” of their day. In the first four decades of the 1800s, they hauled a significant portion of the nation’s long distance freight.
Travelers in Pennsylvania were fascinated by the traffic. On her first trip on the Lancaster Turnpike in May 1810, Sister Catherine Fritsch from Bethlehem marveled at “ten wagons at a wayside mill [waiting] to be loaded with flour for the city” and wagons queued three and four deep, waiting to pay their tolls. Traveling from Philadelphia to Washington, D.C. on the Lancaster stagecoach Josiah Quincy, in 1826, noted that the “road seemed actually lined with Conestoga wagons, each drawn by six stalwart horses, and ladened with farm produce.”
For more than a century, these wagons were the “ships of inland commerce,” hauling large loads on farms and carrying tons of farm produce and freight across Pennsylvania and neighboring states. In the late 1700s, settlers used Conestoga wagons to move them west across the Appalachian Mountains and into the Ohio River valley.
The development of the overland freight industry gave rise to professional “regulars” who teamed for a living, and wagoners or “militiamen,” usually Pennsylvania German farmers, who took up driving as seasonal jobs. Known for their toughness, regulars carried blackjacks and brass knuckles, wore broad-brimmed hats to protect against the sun, smoked cheap cigars called “stogies” – a name derived from their wagons–and had no qualms about forcing another wagon off the road if it challenged their right-of-way. During the summer months, drivers slept and ate on the road, preparing meals and caring for the team on the go. In winter months, they relied on taverns for sustenance and rest.
Wagoners also became a power in Pennsylvania politics. In 1835, they helped elect Joseph “The Wagon Boy of the Alleghenies” Ritner, who has worked as a wagoner in his youth, governor of Pennsylvania. They did their best, too, to hold back public funding of railroads, which they argued would drive up taxes; force blacksmiths, wheelwrights and other tradesmen out of business; stimulate the immigration of “Irishmen by loads”; and ruin “us poor wag’ners.”
The wagoners fears were well-founded. The development of canals and railroads soon ended the use Conestoga wagons as long distance freight carriers in the 1840s. For decades to come, however, they continued to be used on Pennsylvania farms. In the mid-1800s, Pennsylvania’s unique contribution to America’s transportation history also became the moving van of choice for families heading west. Now known as “the prairie schooner” or “covered wagon,” they carried American settlers onto the Great Plains and across the continent to new lives in California and Oregon.
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