An arpent is a unit of length and a unit of area. It is a pre-metric French unit based on the Roman actus. It is used in Quebec as well as in some areas of the United States that were part of French Louisiana.

There were various standard arpents. The most common ones were of 180 French feet, used in French North America, and 220 French feet, used in Paris.

1 arpent = 180 French feet (of approximately 32 centimetres) = about 192 English feet = about 58.47 metres

In Louisiana, parcels of land known as arpent sections or French arpent land grants also pre-date the Public Land Survey System (PLSS), but are treated as PLSS sections. An arpent is a French measurement of approximately 192 feet (59 m), and a square arpent (also referred to as an arpent) is about 0.84 acres (3,400 m²).

French arpent land divisions are long narrow parcels of land usually found along the navigable streams of southern Louisiana, and also found along major waterways in other areas. This system of land subdivision was begun by French settlers in the 18th century, according to typical French practice at the time and was continued by both the Spanish and by the American government after the acquisition of the Louisiana Purchase. A typical French arpent land division is 2 to 4 arpents wide along the river by 40 to 60 arpents deep, while the Spanish arpent land divisions tend to be 6 to 8 arpents wide by 40 arpents deep.