The "square mile (US survey)" is a unit of area used in the United States primarily for land surveying and mapping purposes. It is different from the standard square mile, as it 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 square mile (US survey) is equal to approximately 3,097,600 square square meters (m²) or about 2.589988110336 square kilometers (km²).
This unit is used in various land-related applications, particularly in the United States, where the U.S. survey foot and the square mile (US survey) are still employed for legal and historical reasons in certain land surveys and property descriptions. It is important to be aware of the specific units being used when dealing with land measurements to avoid any discrepancies or errors.
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.