A square chain is a unit of area measurement that is now considered obsolete and not commonly used. It was historically used in some English-speaking countries, including the United States and the United Kingdom, as part of the older system of land measurement.
One square chain is equal to an area of 10 square rods, or 484 square yards. In terms of square meters, one square chain is approximately equal to 404.68564224 square meters (m²).
The square chain was often used in land surveys and property descriptions in the past, but it has been largely replaced by the more standardized metric and imperial systems of measurement. In modern times, square meters and square feet are the more commonly used units for measuring land area.
A square yard (sq yd or yd²) is a unit of area commonly used in the United States and a few other countries. It is defined as the area of a square with sides that each measure one yard (3 feet) in length.
In terms of square feet, one square yard is equal to 9 square feet (1 yard * 1 yard = 3 feet * 3 feet = 9 square feet).
In terms of square meters, one square yard is approximately equal to 0.836127 square meters.
Square yards are often used in various applications, including real estate, landscaping, and construction, especially in the United States where the customary system of measurements is still prevalent.