A hectare (ha) is a unit of area commonly used in many countries, especially in agriculture and land management. It is equal to 10,000 square meters (m²) or 0.01 square kilometers (km²). The term "hectare" is often used to describe the size of large land areas, such as agricultural fields, parks, and estates.
To provide some perspective, a hectare is approximately the size of a square field with sides that are 100 meters (about 328 feet) long. It's a convenient unit for measuring land area in situations where using square meters or square kilometers would result in very large or small numbers.
The "acre (US survey)" is a unit of area used specifically in the United States for land surveying and legal property descriptions. It is different from the standard acre used in other parts of the world. The U.S. survey acre is based on the U.S. survey foot, which is a historical unit of length used in land surveying in the United States. The U.S. survey foot is slightly different from the international foot.
One acre (US survey) is equal to approximately 4,046.872609874252 square meters (m²) or about 0.40468726 hectares (ha).
This unit is used in various land-related applications, especially in the United States, where the U.S. survey acre is employed for legal and historical reasons in land surveys, property descriptions, and land records. It's important to be aware of the specific units being used when dealing with land measurements in the United States to avoid discrepancies or errors.