cobbles

Cobbles are natural rock fragments with sizes between 64 and 256 millimeters in diameter, a category defined by the Wentworth scale. They are larger than pebbles and smaller than boulders and are typically rounded through natural processes such as river or glacial transport.

In civil engineering and landscaping, cobblestones refer to natural stones used for paving roads and walkways. Common choices include granite, basalt, limestone, schist, or sandstone, chosen for durability. The stones are usually set in a bed of mortar or compacted aggregate and sometimes arranged in courses. Unlike setts, which are quarried and cut into regular rectangular blocks, cobbles are naturally shaped and less uniform, giving a characteristic uneven surface.

Historically, cobbled pavement was widely used in Europe and other regions from antiquity into the 19th century. The durable, easily replaceable units could be laid quickly and repaired individually. Surfaces are permeable with good drainage but can be noisy and uneven for wheeled traffic; maintenance often involved resetting displaced stones and repointing joints.

In modern urban design, cobbles are often retained or restored in historic districts for aesthetic and heritage reasons. They may be used selectively for driveways or pedestrian zones or reproduced with machine-cut equivalents. Some contemporary implementations use concrete pavers styled to resemble traditional cobbles while preserving drainage characteristics.

Terminology can vary. In some regions, “cobble” and “cobblestone” are used interchangeably for paving stones sourced from natural rocks, whereas “setts” typically refer to rectangular quarried blocks used for similar purposes.