Cobblestones are stones that were frequently used in the pavement of early streets. "Cobblestone" is derived from the very old English word "cob", which had a wide range of meanings, one of which was "rounded lump" with overtones of large size. "Cobble", which appeared in the 15th century, simply added the diminutive suffix "le" to "cob", and meant a small stone rounded by the flow of water; essentially, a large pebble. It was these smooth "cobbles", gathered from stream beds, that paved the first "cobblestone" streets.
Note that Cobble is a generic geological term for any stone having dimensions between 64–256 mm (2.5–10 inch). A cobbled area is known as a "causey", "cassay" or "cassie" in Scots.
Cobblestones are typically either set in sand or similar material, or are bound together with mortar. Paving with cobblestones allows a road to be heavily used all year long. It prevents the buildup of ruts often found in dirt roads. It has the additional beneficial advantage of not getting muddy in wet weather or dusty in dry weather. A disadvantage is that when compared with modern surfaces, cobble stone paving is quite loud with carriage wheels, horse hooves and modern automobiles. In England for example, custom was to strew the cobbles outside the house of a sick or dying person with straw, so as to dampen the sound. Cobbled streets are highlights in several cycling competitions such as the final Champs-Élysées stage of the Tour de France and the Paris-Roubaix road race as riding upon them is technically more challenging than riding on asphalt.
Cobblestones set in sand have the environmental advantage of being permeable paving, and of flexing (rather than cracking) with movements in the ground.
Cobblestoned and setted streets gradually gave way to macadam roads, and later to tarmac, and finally to asphalt at the beginning of the 20th century. However, cobblestones are often retained in historic areas, even for streets with modern vehicular traffic. Many older villages and cities in Europe are still paved with cobblestones. In recent decades, cobblestones have become a popular material for paving newly pedestrianised streets in Europe. In this case, the noisy nature of the surface is an advantage as pedestrians can hear approaching vehicles.
In older U.S. cities such as Boston, Chicago, Pittsburgh, New York City , San Francisco , Baltimore and Philadelphia, many of the older streets are paved in cobblestones; however, many such streets have been paved over with asphalt, which cracks and erodes away from heavy traffic, thus revealing the original stone pavement. Also, utilities, such as ConEdison often dig up a street and don't bother replacing the stones. Residents of New York City suburbs have been known to steal the stones off from streets and parks for use in their gardens and driveways. In Chicago, the cobblestones are often exposed during street or sewer repair on major arterial streets, along with old streetcar rails (all of which still lie under the street surface in many parts of the city), having simply been paved over.
In some places such as Saskatoon, Saskatchewan, Canada, as late as the 1990s some busy intersections still showed cobblestones through worn down sections of pavement. The cities of Buenos Aires, Argentina, Old San Juan, Puerto Rico and Montevideo, Uruguay, richly influenced by many European architectural features, are well known for their many cobblestone streets, which are still operational and in good condition. They are still maintained and repaired the old fashion way, by placing and arranging granite stones by hand.