Nashua is in southeastern Hillsborough County at 42°45′04″N 71°28′51″W (42.751038, −71.480817).
It is bordered to the south by Middlesex County, Massachusetts.

According to the United States Census Bureau, the city has a total area of 31.9 square miles (82.6 km²), of which 30.8 square miles (79.9 km²) is land and 1.0 square mile (2.7 km²) is water, comprising 3.25% of the city.
The eastern boundary of Nashua is formed by the Merrimack River, and the city is drained by the Nashua River and Salmon Brook, tributaries of the Merrimack.
The Nashua River roughly bisects the city.
Pennichuck Brook forms the city's northern boundary.
The highest point in Nashua is Gilboa Hill in the southern part of the city, at 426 feet (130 m) above sea level.
Nashua is in southeastern Hillsborough County at 42°45′04″N 71°28′51″W (42.751038, −71.480817). It is bordered to the south by Middlesex County, Massachusetts.
According to the United States Census Bureau, the city has a total area of 31.9 square miles (82.6 km²), of which 30.8 square miles (79.9 km²) is land and 1.0 square mile (2.7 km²) is water, comprising 3.25% of the city. The eastern boundary of Nashua is formed by the Merrimack River, and the city is drained by the Nashua River and Salmon Brook, tributaries of the Merrimack. The Nashua River roughly bisects the city. Pennichuck Brook forms the city's northern boundary. The highest point in Nashua is Gilboa Hill in the southern part of the city, at 426 feet (130 m) above sea level.
Nashua, New Hampshire