A square mile (often abbreviated as sq mi or mi²) is a unit of area used primarily in the United States and a few other countries. It is defined as the area of a square with sides that each measure one mile in length. One square mile is equal to 640 acres.
In terms of the International System of Units (SI), one square mile is approximately equal to 2.58999 square kilometers (km²).
To provide some perspective, a square mile is commonly used to describe land areas within cities, counties, and states in the United States. It's a convenient unit for measuring larger land areas, such as the size of cities or counties.
A square rod is a unit of area measurement that is now considered obsolete and not commonly used in modern times. 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 rod is equal to an area of 1/160th of an acre or 1/4,840th of a square yard. In terms of square meters, one square rod is approximately equal to 25.29285264 square meters (m²).
The square rod was often used in land surveys and property descriptions in the past, but it has been largely replaced by more standardized systems of measurement. In modern times, square meters and square feet are the more commonly used units for measuring land area.